class Sequel::Database

A Database object represents a virtual connection to a database. The Database class is meant to be subclassed by database adapters in order to provide the functionality needed for executing queries.

Constants

OPTS

1 - Methods that execute queries and/or return results

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Constants

COLUMN_SCHEMA_DATETIME_TYPES
COLUMN_SCHEMA_STRING_TYPES

Attributes

cache_schema[RW]

Whether the schema should be cached for this database. True by default for performance, can be set to false to always issue a database query to get the schema.

prepared_statements[R]

The prepared statement object hash for this database, keyed by name symbol

Public Instance Methods

<<(sql) click to toggle source

Runs the supplied SQL statement string on the database server. Returns self so it can be safely chained:

DB << "UPDATE albums SET artist_id = NULL" << "DROP TABLE artists"
   # File lib/sequel/database/query.rb
25 def <<(sql)
26   run(sql)
27   self
28 end
call(ps_name, hash=OPTS, &block) click to toggle source

Call the prepared statement with the given name with the given hash of arguments.

DB[:items].where(id: 1).prepare(:first, :sa)
DB.call(:sa) # SELECT * FROM items WHERE id = 1
   # File lib/sequel/database/query.rb
35 def call(ps_name, hash=OPTS, &block)
36   prepared_statement(ps_name).call(hash, &block)
37 end
execute_ddl(sql, opts=OPTS, &block) click to toggle source

Method that should be used when submitting any DDL (Data Definition Language) SQL, such as create_table. By default, calls execute_dui. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
42 def execute_ddl(sql, opts=OPTS, &block)
43   execute_dui(sql, opts, &block)
44 end
execute_dui(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a DELETE or UPDATE statement. By default, calls execute. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
49 def execute_dui(sql, opts=OPTS, &block)
50   execute(sql, opts, &block)
51 end
execute_insert(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a INSERT statement. By default, calls execute_dui. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
56 def execute_insert(sql, opts=OPTS, &block)
57   execute_dui(sql, opts, &block)
58 end
get(*args, &block) click to toggle source

Returns a single value from the database, see Dataset#get.

DB.get(1) # SELECT 1
# => 1
DB.get{server_version.function} # SELECT server_version()
   # File lib/sequel/database/query.rb
65 def get(*args, &block)
66   @default_dataset.get(*args, &block)
67 end
run(sql, opts=OPTS) click to toggle source

Runs the supplied SQL statement string on the database server. Returns nil. Options:

:server

The server to run the SQL on.

DB.run("SET some_server_variable = 42")
   # File lib/sequel/database/query.rb
74 def run(sql, opts=OPTS)
75   sql = literal(sql) if sql.is_a?(SQL::PlaceholderLiteralString)
76   execute_ddl(sql, opts)
77   nil
78 end
schema(table, opts=OPTS) click to toggle source

Returns the schema for the given table as an array with all members being arrays of length 2, the first member being the column name, and the second member being a hash of column information. The table argument can also be a dataset, as long as it only has one table. Available options are:

:reload

Ignore any cached results, and get fresh information from the database.

:schema

An explicit schema to use. It may also be implicitly provided via the table name.

If schema parsing is supported by the database, the column information hash should contain at least the following entries:

:allow_null

Whether NULL is an allowed value for the column.

:db_type

The database type for the column, as a database specific string.

:default

The database default for the column, as a database specific string, or nil if there is no default value.

:primary_key

Whether the columns is a primary key column. If this column is not present, it means that primary key information is unavailable, not that the column is not a primary key.

:ruby_default

The database default for the column, as a ruby object. In many cases, complex database defaults cannot be parsed into ruby objects, in which case nil will be used as the value.

:type

A symbol specifying the type, such as :integer or :string.

Example:

DB.schema(:artists)
# [[:id,
#   {:type=>:integer,
#    :primary_key=>true,
#    :default=>"nextval('artist_id_seq'::regclass)",
#    :ruby_default=>nil,
#    :db_type=>"integer",
#    :allow_null=>false}],
#  [:name,
#   {:type=>:string,
#    :primary_key=>false,
#    :default=>nil,
#    :ruby_default=>nil,
#    :db_type=>"text",
#    :allow_null=>false}]]
    # File lib/sequel/database/query.rb
121 def schema(table, opts=OPTS)
122   raise(Error, 'schema parsing is not implemented on this database') unless supports_schema_parsing?
123 
124   opts = opts.dup
125   tab = if table.is_a?(Dataset)
126     o = table.opts
127     from = o[:from]
128     raise(Error, "can only parse the schema for a dataset with a single from table") unless from && from.length == 1 && !o.include?(:join) && !o.include?(:sql)
129     table.first_source_table
130   else
131     table
132   end
133 
134   qualifiers = split_qualifiers(tab)
135   table_name = qualifiers.pop
136   sch = qualifiers.pop
137   information_schema_schema = case qualifiers.length
138   when 1
139     Sequel.identifier(*qualifiers)
140   when 2
141     Sequel.qualify(*qualifiers)
142   end
143 
144   if table.is_a?(Dataset)
145     quoted_name = table.literal(tab)
146     opts[:dataset] = table
147   else
148     quoted_name = schema_utility_dataset.literal(table)
149   end
150 
151   opts[:schema] = sch if sch && !opts.include?(:schema)
152   opts[:information_schema_schema] = information_schema_schema if information_schema_schema && !opts.include?(:information_schema_schema)
153 
154   Sequel.synchronize{@schemas.delete(quoted_name)} if opts[:reload]
155   if v = Sequel.synchronize{@schemas[quoted_name]}
156     return v
157   end
158 
159   cols = schema_parse_table(table_name, opts)
160   raise(Error, "schema parsing returned no columns, table #{table_name.inspect} probably doesn't exist") if cols.nil? || cols.empty?
161 
162   primary_keys = 0
163   auto_increment_set = false
164   cols.each do |_,c|
165     auto_increment_set = true if c.has_key?(:auto_increment)
166     primary_keys += 1 if c[:primary_key]
167   end
168 
169   cols.each do |_,c|
170     c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type]) unless c.has_key?(:ruby_default)
171     if c[:primary_key] && !auto_increment_set
172       # If adapter didn't set it, assume that integer primary keys are auto incrementing
173       c[:auto_increment] = primary_keys == 1 && !!(c[:db_type] =~ /int/io)
174     end
175     if !c[:max_length] && c[:type] == :string && (max_length = column_schema_max_length(c[:db_type]))
176       c[:max_length] = max_length
177     end
178   end
179   schema_post_process(cols)
180 
181   Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema
182   cols
183 end
table_exists?(name) click to toggle source

Returns true if a table with the given name exists. This requires a query to the database.

DB.table_exists?(:foo) # => false
# SELECT NULL FROM foo LIMIT 1

Note that since this does a SELECT from the table, it can give false negatives if you don't have permission to SELECT from the table.

    # File lib/sequel/database/query.rb
193 def table_exists?(name)
194   sch, table_name = schema_and_table(name)
195   name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
196   ds = from(name)
197   transaction(:savepoint=>:only){_table_exists?(ds)}
198   true
199 rescue DatabaseError
200   false
201 end

Private Instance Methods

_metadata_dataset() click to toggle source

Uncached version of metadata_dataset, designed for overriding.

    # File lib/sequel/database/query.rb
291 def _metadata_dataset
292   dataset
293 end
_table_exists?(ds) click to toggle source

Should raise an error if the table doesn't not exist, and not raise an error if the table does exist.

    # File lib/sequel/database/query.rb
207 def _table_exists?(ds)
208   ds.get(SQL::AliasedExpression.new(Sequel::NULL, :nil))
209 end
column_schema_default_string_type?(type) click to toggle source

Whether the type should be treated as a string type when parsing the column schema default value.

    # File lib/sequel/database/query.rb
213 def column_schema_default_string_type?(type)
214   COLUMN_SCHEMA_STRING_TYPES.include?(type)
215 end
column_schema_default_to_ruby_value(default, type) click to toggle source

Transform the given normalized default string into a ruby object for the given type.

    # File lib/sequel/database/query.rb
219 def column_schema_default_to_ruby_value(default, type)
220   case type
221   when :boolean
222     case default 
223     when /[f0]/i
224       false
225     when /[t1]/i
226       true
227     end
228   when :string, :enum, :set, :interval
229     default
230   when :blob
231     Sequel::SQL::Blob.new(default)
232   when :integer
233     Integer(default)
234   when :float
235     Float(default)
236   when :date
237     Sequel.string_to_date(default)
238   when :datetime
239     DateTime.parse(default)
240   when :time
241     Sequel.string_to_time(default)
242   when :decimal
243     BigDecimal(default)
244   end
245 end
column_schema_max_length(db_type) click to toggle source

Look at the db_type and guess the maximum length of the column. This assumes types such as varchar(255).

    # File lib/sequel/database/query.rb
277 def column_schema_max_length(db_type)
278   if db_type =~ /\((\d+)\)/
279     $1.to_i
280   end
281 end
column_schema_normalize_default(default, type) click to toggle source

Normalize the default value string for the given type and return the normalized value.

    # File lib/sequel/database/query.rb
249 def column_schema_normalize_default(default, type)
250   if column_schema_default_string_type?(type)
251     return unless m = /\A'(.*)'\z/.match(default)
252     m[1].gsub("''", "'")
253   else
254     default
255   end
256 end
column_schema_to_ruby_default(default, type) click to toggle source

Convert the given default, which should be a database specific string, into a ruby object.

    # File lib/sequel/database/query.rb
260 def column_schema_to_ruby_default(default, type)
261   return default unless default.is_a?(String)
262   if COLUMN_SCHEMA_DATETIME_TYPES.include?(type)
263     if /now|today|CURRENT|getdate|\ADate\(\)\z/i.match(default)
264       if type == :date
265         return Sequel::CURRENT_DATE
266       else
267         return Sequel::CURRENT_TIMESTAMP
268       end
269     end
270   end
271   default = column_schema_normalize_default(default, type)
272   column_schema_default_to_ruby_value(default, type) rescue nil
273 end
input_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

    # File lib/sequel/database/query.rb
286 def input_identifier_meth(ds=nil)
287   (ds || dataset).method(:input_identifier)
288 end
metadata_dataset() click to toggle source

Return a dataset that uses the default identifier input and output methods for this database. Used when parsing metadata so that column symbols are returned as expected.

    # File lib/sequel/database/query.rb
298 def metadata_dataset
299   @metadata_dataset ||= _metadata_dataset
300 end
output_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

    # File lib/sequel/database/query.rb
305 def output_identifier_meth(ds=nil)
306   (ds || dataset).method(:output_identifier)
307 end
remove_cached_schema(table) click to toggle source

Remove the cached schema for the given schema name

    # File lib/sequel/database/query.rb
310 def remove_cached_schema(table)
311   cache = @default_dataset.send(:cache)
312   Sequel.synchronize{cache.clear}
313   k = quote_schema_table(table)
314   Sequel.synchronize{@schemas.delete(k)}
315 end
schema_column_type(db_type) click to toggle source

Match the database's column type to a ruby type via a regular expression, and return the ruby type as a symbol such as :integer or :string.

    # File lib/sequel/database/query.rb
320 def schema_column_type(db_type)
321   case db_type
322   when /\A(character( varying)?|n?(var)?char|n?text|string|clob)/io
323     :string
324   when /\A(int(eger)?|(big|small|tiny)int)/io
325     :integer
326   when /\Adate\z/io
327     :date
328   when /\A((small)?datetime|timestamp(\(\d\))?( with(out)? time zone)?)\z/io
329     :datetime
330   when /\Atime( with(out)? time zone)?\z/io
331     :time
332   when /\A(bool(ean)?)\z/io
333     :boolean
334   when /\A(real|float( unsigned)?|double( precision)?|double\(\d+,\d+\)( unsigned)?)\z/io
335     :float
336   when /\A(?:(?:(?:num(?:ber|eric)?|decimal)(?:\(\d+,\s*(\d+|false|true)\))?))\z/io
337     $1 && ['0', 'false'].include?($1) ? :integer : :decimal
338   when /bytea|blob|image|(var)?binary/io
339     :blob
340   when /\Aenum/io
341     :enum
342   end
343 end
schema_post_process(cols) click to toggle source

Post process the schema values.

    # File lib/sequel/database/query.rb
346 def schema_post_process(cols)
347   # :nocov:
348   if RUBY_VERSION >= '2.5'
349   # :nocov:
350     cols.each do |_, h|
351       db_type = h[:db_type]
352       if db_type.is_a?(String)
353         h[:db_type] = -db_type
354       end
355     end
356   end
357 
358   cols.each do |_,c|
359     c.each_value do |val|
360       val.freeze if val.is_a?(String)
361     end
362   end
363 end

2 - Methods that modify the database schema

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Constants

COLUMN_DEFINITION_ORDER

The order of column modifiers to use when defining a column.

COMBINABLE_ALTER_TABLE_OPS

The alter table operations that are combinable.

Public Instance Methods

add_column(table, *args) click to toggle source

Adds a column to the specified table. This method expects a column name, a datatype and optionally a hash with additional constraints and options:

DB.add_column :items, :name, String, unique: true, null: false
DB.add_column :items, :category, String, default: 'ruby'

See alter_table.

   # File lib/sequel/database/schema_methods.rb
25 def add_column(table, *args)
26   alter_table(table) {add_column(*args)}
27 end
add_index(table, columns, options=OPTS) click to toggle source

Adds an index to a table for the given columns:

DB.add_index :posts, :title
DB.add_index :posts, [:author, :title], unique: true

Options:

:ignore_errors

Ignore any DatabaseErrors that are raised

:name

Name to use for index instead of default

See alter_table.

   # File lib/sequel/database/schema_methods.rb
40 def add_index(table, columns, options=OPTS)
41   e = options[:ignore_errors]
42   begin
43     alter_table(table){add_index(columns, options)}
44   rescue DatabaseError
45     raise unless e
46   end
47   nil
48 end
alter_table(name, &block) click to toggle source

Alters the given table with the specified block. Example:

DB.alter_table :items do
  add_column :category, String, default: 'ruby'
  drop_column :category
  rename_column :cntr, :counter
  set_column_type :value, Float
  set_column_default :value, 4.2
  add_index [:group, :category]
  drop_index [:group, :category]
end

Note that add_column accepts all the options available for column definitions using create_table, and add_index accepts all the options available for index definition.

See Schema::AlterTableGenerator and the “Migrations and Schema Modification” guide.

   # File lib/sequel/database/schema_methods.rb
67 def alter_table(name, &block)
68   generator = alter_table_generator(&block)
69   remove_cached_schema(name)
70   apply_alter_table_generator(name, generator)
71   nil
72 end
alter_table_generator(&block) click to toggle source

Return a new Schema::AlterTableGenerator instance with the receiver as the database and the given block.

   # File lib/sequel/database/schema_methods.rb
76 def alter_table_generator(&block)
77   alter_table_generator_class.new(self, &block)
78 end
create_join_table(hash, options=OPTS) click to toggle source

Create a join table using a hash of foreign keys to referenced table names. Example:

create_join_table(cat_id: :cats, dog_id: :dogs)
# CREATE TABLE cats_dogs (
#  cat_id integer NOT NULL REFERENCES cats,
#  dog_id integer NOT NULL REFERENCES dogs,
#  PRIMARY KEY (cat_id, dog_id)
# )
# CREATE INDEX cats_dogs_dog_id_cat_id_index ON cats_dogs(dog_id, cat_id)

The primary key and index are used so that almost all operations on the table can benefit from one of the two indexes, and the primary key ensures that entries in the table are unique, which is the typical desire for a join table.

The default table name this will create is the sorted version of the two hash values, joined by an underscore. So the following two method calls create the same table:

create_join_table(cat_id: :cats, dog_id: :dogs) # cats_dogs
create_join_table(dog_id: :dogs, cat_id: :cats) # cats_dogs

You can provide column options by making the values in the hash be option hashes, so long as the option hashes have a :table entry giving the table referenced:

create_join_table(cat_id: {table: :cats, type: :Bignum}, dog_id: :dogs)

You can provide a second argument which is a table options hash:

create_join_table({cat_id: :cats, dog_id: :dogs}, temp: true)

Some table options are handled specially:

:index_options

The options to pass to the index

:name

The name of the table to create

:no_index

Set to true not to create the second index.

:no_primary_key

Set to true to not create the primary key.

    # File lib/sequel/database/schema_methods.rb
119 def create_join_table(hash, options=OPTS)
120   keys = hash.keys.sort
121   create_table(join_table_name(hash, options), options) do
122     keys.each do |key|
123       v = hash[key]
124       unless v.is_a?(Hash)
125         v = {:table=>v}
126       end
127       v[:null] = false unless v.has_key?(:null)
128       foreign_key(key, v)
129     end
130     primary_key(keys) unless options[:no_primary_key]
131     index(keys.reverse, options[:index_options] || OPTS) unless options[:no_index]
132   end
133   nil
134 end
create_join_table!(hash, options=OPTS) click to toggle source

Forcibly create a join table, attempting to drop it if it already exists, then creating it.

    # File lib/sequel/database/schema_methods.rb
137 def create_join_table!(hash, options=OPTS)
138   drop_table?(join_table_name(hash, options))
139   create_join_table(hash, options)
140 end
create_join_table?(hash, options=OPTS) click to toggle source

Creates the join table unless it already exists.

    # File lib/sequel/database/schema_methods.rb
143 def create_join_table?(hash, options=OPTS)
144   if supports_create_table_if_not_exists? && options[:no_index]
145     create_join_table(hash, options.merge(:if_not_exists=>true))
146   elsif !table_exists?(join_table_name(hash, options))
147     create_join_table(hash, options)
148   end
149 end
create_or_replace_view(name, source, options = OPTS) click to toggle source

Creates a view, replacing a view with the same name if one already exists.

DB.create_or_replace_view(:some_items, "SELECT * FROM items WHERE price < 100")
DB.create_or_replace_view(:some_items, DB[:items].where(category: 'ruby'))

For databases where replacing a view is not natively supported, support is emulated by dropping a view with the same name before creating the view.

    # File lib/sequel/database/schema_methods.rb
239 def create_or_replace_view(name, source, options = OPTS)
240   if supports_create_or_replace_view?
241     options = options.merge(:replace=>true)
242   else
243     swallow_database_error{drop_view(name)}
244   end
245 
246   create_view(name, source, options)
247   nil
248 end
create_table(name, options=OPTS, &block) click to toggle source

Creates a table with the columns given in the provided block:

DB.create_table :posts do
  primary_key :id
  column :title, String
  String :content
  index :title
end

General options:

:as

Create the table using the value, which should be either a dataset or a literal SQL string. If this option is used, a block should not be given to the method.

:ignore_index_errors

Ignore any errors when creating indexes.

:temp

Create the table as a temporary table.

MySQL specific options:

:charset

The character set to use for the table.

:collate

The collation to use for the table.

:engine

The table engine to use for the table.

PostgreSQL specific options:

:on_commit

Either :preserve_rows (default), :drop or :delete_rows. Should only be specified when creating a temporary table.

:foreign

Create a foreign table. The value should be the name of the foreign server that was specified in CREATE SERVER.

:inherits

Inherit from a different table. An array can be specified to inherit from multiple tables.

:unlogged

Create the table as an unlogged table.

:options

The OPTIONS clause to use for foreign tables. Should be a hash where keys are option names and values are option values. Note that option names are unquoted, so you should not use untrusted keys.

:tablespace

The tablespace to use for the table.

See Schema::CreateTableGenerator and the “Schema Modification” guide.

    # File lib/sequel/database/schema_methods.rb
187 def create_table(name, options=OPTS, &block)
188   remove_cached_schema(name)
189   if sql = options[:as]
190     raise(Error, "can't provide both :as option and block to create_table") if block
191     create_table_as(name, sql, options)
192   else
193     generator = options[:generator] || create_table_generator(&block)
194     create_table_from_generator(name, generator, options)
195     create_table_indexes_from_generator(name, generator, options)
196   end
197   nil
198 end
create_table!(name, options=OPTS, &block) click to toggle source

Forcibly create a table, attempting to drop it if it already exists, then creating it.

DB.create_table!(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- drop table if already exists
# CREATE TABLE a (a integer)
    # File lib/sequel/database/schema_methods.rb
206 def create_table!(name, options=OPTS, &block)
207   drop_table?(name)
208   create_table(name, options, &block)
209 end
create_table?(name, options=OPTS, &block) click to toggle source

Creates the table unless the table already exists.

DB.create_table?(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# CREATE TABLE a (a integer) -- if it doesn't already exist
    # File lib/sequel/database/schema_methods.rb
216 def create_table?(name, options=OPTS, &block)
217   options = options.dup
218   generator = options[:generator] ||= create_table_generator(&block)
219   if generator.indexes.empty? && supports_create_table_if_not_exists?
220     create_table(name, options.merge!(:if_not_exists=>true))
221   elsif !table_exists?(name)
222     create_table(name, options)
223   end
224 end
create_table_generator(&block) click to toggle source

Return a new Schema::CreateTableGenerator instance with the receiver as the database and the given block.

    # File lib/sequel/database/schema_methods.rb
228 def create_table_generator(&block)
229   create_table_generator_class.new(self, &block)
230 end
create_view(name, source, options = OPTS) click to toggle source

Creates a view based on a dataset or an SQL string:

DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100")
# CREATE VIEW cheap_items AS
# SELECT * FROM items WHERE price < 100

DB.create_view(:ruby_items, DB[:items].where(category: 'ruby'))
# CREATE VIEW ruby_items AS
# SELECT * FROM items WHERE (category = 'ruby')

DB.create_view(:checked_items, DB[:items].where(:foo), check: true)
# CREATE VIEW checked_items AS
# SELECT * FROM items WHERE foo
# WITH CHECK OPTION

Options:

:columns

The column names to use for the view. If not given, automatically determined based on the input dataset.

:check

Adds a WITH CHECK OPTION clause, so that attempting to modify rows in the underlying table that would not be returned by the view is not allowed. This can be set to :local to use WITH LOCAL CHECK OPTION.

PostgreSQL/SQLite specific option:

:temp

Create a temporary view, automatically dropped on disconnect.

PostgreSQL specific options:

:materialized

Creates a materialized view, similar to a regular view, but backed by a physical table.

:recursive

Creates a recursive view. As columns must be specified for recursive views, you can also set them as the value of this option. Since a recursive view requires a union that isn't in a subquery, if you are providing a Dataset as the source argument, if should probably call the union method with the all: true and from_self: false options.

:tablespace

The tablespace to use for materialized views.

    # File lib/sequel/database/schema_methods.rb
286 def create_view(name, source, options = OPTS)
287   execute_ddl(create_view_sql(name, source, options))
288   remove_cached_schema(name)
289   nil
290 end
drop_column(table, *args) click to toggle source

Removes a column from the specified table:

DB.drop_column :items, :category

See alter_table.

    # File lib/sequel/database/schema_methods.rb
297 def drop_column(table, *args)
298   alter_table(table) {drop_column(*args)}
299 end
drop_index(table, columns, options=OPTS) click to toggle source

Removes an index for the given table and column(s):

DB.drop_index :posts, :title
DB.drop_index :posts, [:author, :title]

See alter_table.

    # File lib/sequel/database/schema_methods.rb
307 def drop_index(table, columns, options=OPTS)
308   alter_table(table){drop_index(columns, options)}
309 end
drop_join_table(hash, options=OPTS) click to toggle source

Drop the join table that would have been created with the same arguments to create_join_table:

drop_join_table(cat_id: :cats, dog_id: :dogs)
# DROP TABLE cats_dogs
    # File lib/sequel/database/schema_methods.rb
316 def drop_join_table(hash, options=OPTS)
317   drop_table(join_table_name(hash, options), options)
318 end
drop_table(*names) click to toggle source

Drops one or more tables corresponding to the given names:

DB.drop_table(:posts) # DROP TABLE posts
DB.drop_table(:posts, :comments)
DB.drop_table(:posts, :comments, cascade: true)
    # File lib/sequel/database/schema_methods.rb
325 def drop_table(*names)
326   options = names.last.is_a?(Hash) ? names.pop : OPTS 
327   names.each do |n|
328     execute_ddl(drop_table_sql(n, options))
329     remove_cached_schema(n)
330   end
331   nil
332 end
drop_table?(*names) click to toggle source

Drops the table if it already exists. If it doesn't exist, does nothing.

DB.drop_table?(:a)
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- if it already exists
    # File lib/sequel/database/schema_methods.rb
340 def drop_table?(*names)
341   options = names.last.is_a?(Hash) ? names.pop : OPTS
342   if supports_drop_table_if_exists?
343     options = options.merge(:if_exists=>true)
344     names.each do |name|
345       drop_table(name, options)
346     end
347   else
348     names.each do |name|
349       drop_table(name, options) if table_exists?(name)
350     end
351   end
352   nil
353 end
drop_view(*names) click to toggle source

Drops one or more views corresponding to the given names:

DB.drop_view(:cheap_items)
DB.drop_view(:cheap_items, :pricey_items)
DB.drop_view(:cheap_items, :pricey_items, cascade: true)
DB.drop_view(:cheap_items, :pricey_items, if_exists: true)

Options:

:cascade

Also drop objects depending on this view.

:if_exists

Do not raise an error if the view does not exist.

PostgreSQL specific options:

:materialized

Drop a materialized view.

    # File lib/sequel/database/schema_methods.rb
368 def drop_view(*names)
369   options = names.last.is_a?(Hash) ? names.pop : OPTS
370   names.each do |n|
371     execute_ddl(drop_view_sql(n, options))
372     remove_cached_schema(n)
373   end
374   nil
375 end
rename_column(table, *args) click to toggle source

Renames a column in the specified table. This method expects the current column name and the new column name:

DB.rename_column :items, :cntr, :counter

See alter_table.

    # File lib/sequel/database/schema_methods.rb
394 def rename_column(table, *args)
395   alter_table(table) {rename_column(*args)}
396 end
rename_table(name, new_name) click to toggle source

Renames a table:

DB.tables #=> [:items]
DB.rename_table :items, :old_items
DB.tables #=> [:old_items]
    # File lib/sequel/database/schema_methods.rb
382 def rename_table(name, new_name)
383   execute_ddl(rename_table_sql(name, new_name))
384   remove_cached_schema(name)
385   nil
386 end
set_column_default(table, *args) click to toggle source

Sets the default value for the given column in the given table:

DB.set_column_default :items, :category, 'perl!'

See alter_table.

    # File lib/sequel/database/schema_methods.rb
403 def set_column_default(table, *args)
404   alter_table(table) {set_column_default(*args)}
405 end
set_column_type(table, *args) click to toggle source

Set the data type for the given column in the given table:

DB.set_column_type :items, :price, :float

See alter_table.

    # File lib/sequel/database/schema_methods.rb
412 def set_column_type(table, *args)
413   alter_table(table) {set_column_type(*args)}
414 end

Private Instance Methods

alter_table_add_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
452 def alter_table_add_column_sql(table, op)
453   "ADD COLUMN #{column_definition_sql(op)}"
454 end
alter_table_add_constraint_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
476 def alter_table_add_constraint_sql(table, op)
477   "ADD #{constraint_definition_sql(op)}"
478 end
alter_table_drop_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
456 def alter_table_drop_column_sql(table, op)
457   "DROP COLUMN #{quote_identifier(op[:name])}#{' CASCADE' if op[:cascade]}"
458 end
alter_table_drop_constraint_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
480 def alter_table_drop_constraint_sql(table, op)
481   quoted_name = quote_identifier(op[:name]) if op[:name]
482   if op[:type] == :foreign_key
483     quoted_name ||= quote_identifier(foreign_key_name(table, op[:columns]))
484   end
485   "DROP CONSTRAINT #{quoted_name}#{' CASCADE' if op[:cascade]}"
486 end
alter_table_generator_class() click to toggle source

The class used for alter_table generators.

    # File lib/sequel/database/schema_methods.rb
437 def alter_table_generator_class
438   Schema::AlterTableGenerator
439 end
alter_table_op_sql(table, op) click to toggle source

SQL fragment for given alter table operation.

    # File lib/sequel/database/schema_methods.rb
442 def alter_table_op_sql(table, op)
443   meth = "alter_table_#{op[:op]}_sql"
444   if respond_to?(meth, true)
445     # Allow calling private methods as alter table op sql methods are private
446     send(meth, table, op)
447   else
448     raise Error, "Unsupported ALTER TABLE operation: #{op[:op]}"
449   end
450 end
alter_table_rename_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
460 def alter_table_rename_column_sql(table, op)
461   "RENAME COLUMN #{quote_identifier(op[:name])} TO #{quote_identifier(op[:new_name])}"
462 end
alter_table_set_column_default_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
468 def alter_table_set_column_default_sql(table, op)
469   "ALTER COLUMN #{quote_identifier(op[:name])} SET DEFAULT #{literal(op[:default])}"
470 end
alter_table_set_column_null_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
472 def alter_table_set_column_null_sql(table, op)
473   "ALTER COLUMN #{quote_identifier(op[:name])} #{op[:null] ? 'DROP' : 'SET'} NOT NULL"
474 end
alter_table_set_column_type_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
464 def alter_table_set_column_type_sql(table, op)
465   "ALTER COLUMN #{quote_identifier(op[:name])} TYPE #{type_literal(op)}"
466 end
alter_table_sql(table, op) click to toggle source

The SQL to execute to modify the table. op should be one of the operations returned by the AlterTableGenerator.

    # File lib/sequel/database/schema_methods.rb
490 def alter_table_sql(table, op)
491   case op[:op]
492   when :add_index
493     index_definition_sql(table, op)
494   when :drop_index
495     drop_index_sql(table, op)
496   else
497     if sql = alter_table_op_sql(table, op)
498       "ALTER TABLE #{quote_schema_table(table)} #{sql}"
499     end
500   end
501 end
alter_table_sql_list(table, operations) click to toggle source

Array of SQL statements used to modify the table, corresponding to changes specified by the operations.

    # File lib/sequel/database/schema_methods.rb
505 def alter_table_sql_list(table, operations)
506   if supports_combining_alter_table_ops?
507     grouped_ops = []
508     last_combinable = false
509     operations.each do |op|
510       if combinable_alter_table_op?(op)
511         if sql = alter_table_op_sql(table, op)
512           grouped_ops << [] unless last_combinable
513           grouped_ops.last << sql
514           last_combinable = true
515         end
516       elsif sql = alter_table_sql(table, op)
517         Array(sql).each{|s| grouped_ops << s}
518         last_combinable = false
519       end
520     end
521     grouped_ops.map do |gop|
522       if gop.is_a?(Array)
523         "ALTER TABLE #{quote_schema_table(table)} #{gop.join(', ')}"
524       else
525         gop
526       end
527     end
528   else
529     operations.map{|op| alter_table_sql(table, op)}.flatten.compact
530   end
531 end
apply_alter_table(name, ops) click to toggle source

Apply the changes in the given alter table ops to the table given by name.

    # File lib/sequel/database/schema_methods.rb
419 def apply_alter_table(name, ops)
420   alter_table_sql_list(name, ops).each{|sql| execute_ddl(sql)}
421 end
apply_alter_table_generator(name, generator) click to toggle source

Apply the operations in the given generator to the table given by name.

    # File lib/sequel/database/schema_methods.rb
424 def apply_alter_table_generator(name, generator)
425   ops = generator.operations
426 
427   unless can_add_primary_key_constraint_on_nullable_columns?
428     if add_pk = ops.find{|op| op[:op] == :add_constraint && op[:type] == :primary_key}
429       ops = add_pk[:columns].map{|column| {:op => :set_column_null, :name => column, :null => false}} + ops
430     end
431   end
432 
433   apply_alter_table(name, ops)
434 end
auto_increment_sql() click to toggle source

The SQL string specify the autoincrement property, generally used by primary keys.

    # File lib/sequel/database/schema_methods.rb
535 def auto_increment_sql
536   'AUTOINCREMENT'
537 end
column_definition_auto_increment_sql(sql, column) click to toggle source

Add auto increment SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
553 def column_definition_auto_increment_sql(sql, column)
554   sql << " #{auto_increment_sql}" if column[:auto_increment]
555 end
column_definition_collate_sql(sql, column) click to toggle source

Add collate SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
558 def column_definition_collate_sql(sql, column)
559   if collate = column[:collate]
560     sql << " COLLATE #{collate}"
561   end
562 end
column_definition_default_sql(sql, column) click to toggle source

Add default SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
565 def column_definition_default_sql(sql, column)
566   sql << " DEFAULT #{literal(column[:default])}" if column.include?(:default)
567 end
column_definition_null_sql(sql, column) click to toggle source

Add null/not null SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
570 def column_definition_null_sql(sql, column)
571   null = column.fetch(:null, column[:allow_null])
572   if null.nil? && !can_add_primary_key_constraint_on_nullable_columns? && column[:primary_key]
573     null = false
574   end
575 
576   case null
577   when false
578     sql << ' NOT NULL'
579   when true
580     sql << ' NULL'
581   end
582 end
column_definition_order() click to toggle source

The order of the column definition, as an array of symbols.

    # File lib/sequel/database/schema_methods.rb
540 def column_definition_order
541   COLUMN_DEFINITION_ORDER
542 end
column_definition_primary_key_sql(sql, column) click to toggle source

Add primary key SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
585 def column_definition_primary_key_sql(sql, column)
586   if column[:primary_key]
587     if name = column[:primary_key_constraint_name]
588       sql << " CONSTRAINT #{quote_identifier(name)}"
589     end
590     sql << " " << primary_key_constraint_sql_fragment(column)
591     constraint_deferrable_sql_append(sql, column[:primary_key_deferrable])
592   end
593 end
column_definition_references_sql(sql, column) click to toggle source

Add foreign key reference SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
596 def column_definition_references_sql(sql, column)
597   if column[:table]
598     if name = column[:foreign_key_constraint_name]
599      sql << " CONSTRAINT #{quote_identifier(name)}"
600     end
601     sql << column_references_column_constraint_sql(column)
602   end
603 end
column_definition_sql(column) click to toggle source

SQL fragment containing the column creation SQL for the given column.

    # File lib/sequel/database/schema_methods.rb
545 def column_definition_sql(column)
546   sql = String.new
547   sql << "#{quote_identifier(column[:name])} #{type_literal(column)}"
548   column_definition_order.each{|m| send(:"column_definition_#{m}_sql", sql, column)}
549   sql
550 end
column_definition_unique_sql(sql, column) click to toggle source

Add unique constraint SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
606 def column_definition_unique_sql(sql, column)
607   if column[:unique]
608     if name = column[:unique_constraint_name]
609       sql << " CONSTRAINT #{quote_identifier(name)}"
610     end
611     sql << ' ' << unique_constraint_sql_fragment(column)
612     constraint_deferrable_sql_append(sql, column[:unique_deferrable])
613   end
614 end
column_list_sql(generator) click to toggle source

SQL for all given columns, used inside a CREATE TABLE block.

    # File lib/sequel/database/schema_methods.rb
617 def column_list_sql(generator)
618   (generator.columns.map{|c| column_definition_sql(c)} + generator.constraints.map{|c| constraint_definition_sql(c)}).join(', ')
619 end
column_references_column_constraint_sql(column) click to toggle source

SQL fragment for column foreign key references (column constraints)

    # File lib/sequel/database/schema_methods.rb
622 def column_references_column_constraint_sql(column)
623   column_references_sql(column)
624 end
column_references_sql(column) click to toggle source

SQL fragment for column foreign key references

    # File lib/sequel/database/schema_methods.rb
627 def column_references_sql(column)
628   sql = String.new
629   sql << " REFERENCES #{quote_schema_table(column[:table])}"
630   sql << "(#{Array(column[:key]).map{|x| quote_identifier(x)}.join(', ')})" if column[:key]
631   sql << " ON DELETE #{on_delete_clause(column[:on_delete])}" if column[:on_delete]
632   sql << " ON UPDATE #{on_update_clause(column[:on_update])}" if column[:on_update]
633   constraint_deferrable_sql_append(sql, column[:deferrable])
634   sql
635 end
column_references_table_constraint_sql(constraint) click to toggle source

SQL fragment for table foreign key references (table constraints)

    # File lib/sequel/database/schema_methods.rb
638 def column_references_table_constraint_sql(constraint)
639   "FOREIGN KEY #{literal(constraint[:columns])}#{column_references_sql(constraint)}"
640 end
combinable_alter_table_op?(op) click to toggle source

Whether the given alter table operation is combinable.

    # File lib/sequel/database/schema_methods.rb
643 def combinable_alter_table_op?(op)
644   COMBINABLE_ALTER_TABLE_OPS.include?(op[:op])
645 end
constraint_deferrable_sql_append(sql, defer) click to toggle source

SQL fragment specifying the deferrable constraint attributes.

    # File lib/sequel/database/schema_methods.rb
672 def constraint_deferrable_sql_append(sql, defer)
673   case defer
674   when nil
675   when false
676     sql << ' NOT DEFERRABLE'
677   when :immediate
678     sql << ' DEFERRABLE INITIALLY IMMEDIATE'
679   else
680     sql << ' DEFERRABLE INITIALLY DEFERRED'
681   end
682 end
constraint_definition_sql(constraint) click to toggle source

SQL fragment specifying a constraint on a table.

    # File lib/sequel/database/schema_methods.rb
648 def constraint_definition_sql(constraint)
649   sql = String.new
650   sql << "CONSTRAINT #{quote_identifier(constraint[:name])} " if constraint[:name] 
651   case constraint[:type]
652   when :check
653     check = constraint[:check]
654     check = check.first if check.is_a?(Array) && check.length == 1
655     check = filter_expr(check)
656     check = "(#{check})" unless check[0..0] == '(' && check[-1..-1] == ')'
657     sql << "CHECK #{check}"
658   when :primary_key
659     sql << "#{primary_key_constraint_sql_fragment(constraint)} #{literal(constraint[:columns])}"
660   when :foreign_key
661     sql << column_references_table_constraint_sql(constraint.merge(:deferrable=>nil))
662   when :unique
663     sql << "#{unique_constraint_sql_fragment(constraint)} #{literal(constraint[:columns])}"
664   else
665     raise Error, "Invalid constraint type #{constraint[:type]}, should be :check, :primary_key, :foreign_key, or :unique"
666   end
667   constraint_deferrable_sql_append(sql, constraint[:deferrable])
668   sql
669 end
create_table_as(name, sql, options) click to toggle source

Run SQL statement to create the table with the given name from the given SELECT sql statement.

    # File lib/sequel/database/schema_methods.rb
742 def create_table_as(name, sql, options)
743   sql = sql.sql if sql.is_a?(Sequel::Dataset)
744   run(create_table_as_sql(name, sql, options))
745 end
create_table_as_sql(name, sql, options) click to toggle source

SQL statement for creating a table from the result of a SELECT statement. sql should be a string representing a SELECT query.

    # File lib/sequel/database/schema_methods.rb
749 def create_table_as_sql(name, sql, options)
750   "#{create_table_prefix_sql(name, options)} AS #{sql}"
751 end
create_table_from_generator(name, generator, options) click to toggle source

Execute the create table statements using the generator.

    # File lib/sequel/database/schema_methods.rb
685 def create_table_from_generator(name, generator, options)
686   execute_ddl(create_table_sql(name, generator, options))
687 end
create_table_generator_class() click to toggle source

The class used for create_table generators.

    # File lib/sequel/database/schema_methods.rb
690 def create_table_generator_class
691   Schema::CreateTableGenerator
692 end
create_table_indexes_from_generator(name, generator, options) click to toggle source

Execute the create index statements using the generator.

    # File lib/sequel/database/schema_methods.rb
695 def create_table_indexes_from_generator(name, generator, options)
696   e = options[:ignore_index_errors] || options[:if_not_exists]
697   generator.indexes.each do |index|
698     begin
699       pr = proc{index_sql_list(name, [index]).each{|sql| execute_ddl(sql)}}
700       supports_transactional_ddl? ? transaction(:savepoint=>:only, &pr) : pr.call
701     rescue Error
702       raise unless e
703     end
704   end
705 end
create_table_prefix_sql(name, options) click to toggle source

SQL fragment for initial part of CREATE TABLE statement

    # File lib/sequel/database/schema_methods.rb
754 def create_table_prefix_sql(name, options)
755   "CREATE #{temporary_table_sql if options[:temp]}TABLE#{' IF NOT EXISTS' if options[:if_not_exists]} #{options[:temp] ? quote_identifier(name) : quote_schema_table(name)}"
756 end
create_table_sql(name, generator, options) click to toggle source

SQL statement for creating a table with the given name, columns, and options

    # File lib/sequel/database/schema_methods.rb
708 def create_table_sql(name, generator, options)
709   unless supports_named_column_constraints?
710     # Split column constraints into table constraints if they have a name
711     generator.columns.each do |c|
712       if (constraint_name = c.delete(:foreign_key_constraint_name)) && (table = c.delete(:table))
713         opts = {}
714         opts[:name] = constraint_name
715         [:key, :on_delete, :on_update, :deferrable].each{|k| opts[k] = c[k]}
716         generator.foreign_key([c[:name]], table, opts)
717       end
718       if (constraint_name = c.delete(:unique_constraint_name)) && c.delete(:unique)
719         generator.unique(c[:name], :name=>constraint_name)
720       end
721       if (constraint_name = c.delete(:primary_key_constraint_name)) && c.delete(:primary_key)
722         generator.primary_key([c[:name]], :name=>constraint_name)
723       end
724     end
725   end
726 
727   unless can_add_primary_key_constraint_on_nullable_columns?
728     if pk = generator.constraints.find{|op| op[:type] == :primary_key}
729       pk[:columns].each do |column|
730         if matched_column = generator.columns.find{|gc| gc[:name] == column}
731           matched_column[:null] = false
732         end
733       end
734     end
735   end
736 
737   "#{create_table_prefix_sql(name, options)} (#{column_list_sql(generator)})"
738 end
create_view_prefix_sql(name, options) click to toggle source

SQL fragment for initial part of CREATE VIEW statement

    # File lib/sequel/database/schema_methods.rb
759 def create_view_prefix_sql(name, options)
760   create_view_sql_append_columns("CREATE #{'OR REPLACE 'if options[:replace]}VIEW #{quote_schema_table(name)}", options[:columns])
761 end
create_view_sql(name, source, options) click to toggle source

SQL statement for creating a view.

    # File lib/sequel/database/schema_methods.rb
764 def create_view_sql(name, source, options)
765   source = source.sql if source.is_a?(Dataset)
766   sql = String.new
767   sql << "#{create_view_prefix_sql(name, options)} AS #{source}"
768   if check = options[:check]
769     sql << " WITH#{' LOCAL' if check == :local} CHECK OPTION"
770   end
771   sql
772 end
create_view_sql_append_columns(sql, columns) click to toggle source

Append the column list to the SQL, if a column list is given.

    # File lib/sequel/database/schema_methods.rb
775 def create_view_sql_append_columns(sql, columns)
776   if columns
777     sql += ' ('
778     schema_utility_dataset.send(:identifier_list_append, sql, columns)
779     sql << ')'
780   end
781   sql
782 end
default_index_name(table_name, columns) click to toggle source

Default index name for the table and columns, may be too long for certain databases.

    # File lib/sequel/database/schema_methods.rb
786 def default_index_name(table_name, columns)
787   schema, table = schema_and_table(table_name)
788   "#{"#{schema}_" if schema}#{table}_#{columns.map{|c| [String, Symbol].any?{|cl| c.is_a?(cl)} ? c : literal(c).gsub(/\W/, '_')}.join('_')}_index"
789 end
drop_index_sql(table, op) click to toggle source

The SQL to drop an index for the table.

    # File lib/sequel/database/schema_methods.rb
799 def drop_index_sql(table, op)
800   "DROP INDEX #{quote_identifier(op[:name] || default_index_name(table, op[:columns]))}"
801 end
drop_table_sql(name, options) click to toggle source

SQL DDL statement to drop the table with the given name.

    # File lib/sequel/database/schema_methods.rb
804 def drop_table_sql(name, options)
805   "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
806 end
drop_view_sql(name, options) click to toggle source

SQL DDL statement to drop a view with the given name.

    # File lib/sequel/database/schema_methods.rb
809 def drop_view_sql(name, options)
810   "DROP VIEW#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
811 end
filter_expr(arg=nil, &block) click to toggle source

Proxy the filter_expr call to the dataset, used for creating constraints. Support passing Proc arguments as blocks, as well as treating plain strings as literal strings, so that previous migrations that used this API do not break.

    # File lib/sequel/database/schema_methods.rb
816 def filter_expr(arg=nil, &block)
817   if arg.is_a?(Proc) && !block
818     block = arg
819     arg = nil
820   elsif arg.is_a?(String)
821     arg = Sequel.lit(arg)
822   elsif arg.is_a?(Array)
823     if arg.first.is_a?(String)
824       arg = Sequel.lit(*arg)
825     elsif arg.length > 1
826       arg = Sequel.&(*arg)
827     end
828   end
829   schema_utility_dataset.literal(schema_utility_dataset.send(:filter_expr, arg, &block))
830 end
foreign_key_name(table_name, columns) click to toggle source

Get foreign key name for given table and columns.

    # File lib/sequel/database/schema_methods.rb
792 def foreign_key_name(table_name, columns)
793   keys = foreign_key_list(table_name).select{|key| key[:columns] == columns}
794   raise(Error, "#{keys.empty? ? 'Missing' : 'Ambiguous'} foreign key for #{columns.inspect}") unless keys.size == 1
795   keys.first[:name]
796 end
index_definition_sql(table_name, index) click to toggle source

SQL statement for creating an index for the table with the given name and index specifications.

    # File lib/sequel/database/schema_methods.rb
834 def index_definition_sql(table_name, index)
835   index_name = index[:name] || default_index_name(table_name, index[:columns])
836   raise Error, "Index types are not supported for this database" if index[:type]
837   raise Error, "Partial indexes are not supported for this database" if index[:where] && !supports_partial_indexes?
838   "CREATE #{'UNIQUE ' if index[:unique]}INDEX #{quote_identifier(index_name)} ON #{quote_schema_table(table_name)} #{literal(index[:columns])}#{" WHERE #{filter_expr(index[:where])}" if index[:where]}"
839 end
index_sql_list(table_name, indexes) click to toggle source

Array of SQL statements, one for each index specification, for the given table.

    # File lib/sequel/database/schema_methods.rb
843 def index_sql_list(table_name, indexes)
844   indexes.map{|i| index_definition_sql(table_name, i)}
845 end
join_table_name(hash, options) click to toggle source

Extract the join table name from the arguments given to create_join_table. Also does argument validation for the create_join_table method.

    # File lib/sequel/database/schema_methods.rb
849 def join_table_name(hash, options)
850   entries = hash.values
851   raise Error, "must have 2 entries in hash given to (create|drop)_join_table" unless entries.length == 2
852   if options[:name]
853     options[:name]
854   else
855     table_names = entries.map{|e| join_table_name_extract(e)}
856     table_names.map(&:to_s).sort.join('_')
857   end
858 end
join_table_name_extract(entry) click to toggle source

Extract an individual join table name, which should either be a string or symbol, or a hash containing one of those as the value for :table.

    # File lib/sequel/database/schema_methods.rb
862 def join_table_name_extract(entry)
863   case entry
864   when Symbol, String
865     entry
866   when Hash
867     join_table_name_extract(entry[:table])
868   else
869     raise Error, "can't extract table name from #{entry.inspect}"
870   end
871 end
on_delete_clause(action) click to toggle source

SQL fragment to use for ON DELETE, based on the given action. The following actions are recognized:

:cascade

Delete rows referencing this row.

:no_action

Raise an error if other rows reference this row, allow deferring of the integrity check. This is the default.

:restrict

Raise an error if other rows reference this row, but do not allow deferring the integrity check.

:set_default

Set columns referencing this row to their default value.

:set_null

Set columns referencing this row to NULL.

Any other object given is just converted to a string, with “_” converted to “ ” and upcased.

    # File lib/sequel/database/schema_methods.rb
886 def on_delete_clause(action)
887   action.to_s.gsub("_", " ").upcase
888 end
on_update_clause(action) click to toggle source

Alias of on_delete_clause, since the two usually behave the same.

    # File lib/sequel/database/schema_methods.rb
891 def on_update_clause(action)
892   on_delete_clause(action)
893 end
primary_key_constraint_sql_fragment(_) click to toggle source

Add fragment for primary key specification, separated for easier overridding.

    # File lib/sequel/database/schema_methods.rb
896 def primary_key_constraint_sql_fragment(_)
897   'PRIMARY KEY'
898 end
quote_schema_table(table) click to toggle source

Proxy the quote_schema_table method to the dataset

    # File lib/sequel/database/schema_methods.rb
901 def quote_schema_table(table)
902   schema_utility_dataset.quote_schema_table(table)
903 end
rename_table_sql(name, new_name) click to toggle source

SQL statement for renaming a table.

    # File lib/sequel/database/schema_methods.rb
906 def rename_table_sql(name, new_name)
907   "ALTER TABLE #{quote_schema_table(name)} RENAME TO #{quote_schema_table(new_name)}"
908 end
schema_and_table(table_name) click to toggle source

Split the schema information from the table

    # File lib/sequel/database/schema_methods.rb
911 def schema_and_table(table_name)
912   schema_utility_dataset.schema_and_table(table_name)
913 end
schema_autoincrementing_primary_key?(schema) click to toggle source

Return true if the given column schema represents an autoincrementing primary key.

    # File lib/sequel/database/schema_methods.rb
916 def schema_autoincrementing_primary_key?(schema)
917   !!(schema[:primary_key] && schema[:auto_increment])
918 end
schema_utility_dataset() click to toggle source

The dataset to use for proxying certain schema methods.

    # File lib/sequel/database/schema_methods.rb
921 def schema_utility_dataset
922   @default_dataset
923 end
split_qualifiers(table_name) click to toggle source

Split the schema information from the table

    # File lib/sequel/database/schema_methods.rb
926 def split_qualifiers(table_name)
927   schema_utility_dataset.split_qualifiers(table_name)
928 end
temporary_table_sql() click to toggle source

SQL fragment for temporary table

    # File lib/sequel/database/schema_methods.rb
931 def temporary_table_sql
932   'TEMPORARY '
933 end
type_literal(column) click to toggle source

SQL fragment specifying the type of a given column.

    # File lib/sequel/database/schema_methods.rb
936 def type_literal(column)
937   case column[:type]
938   when Class
939     type_literal_generic(column)
940   when :Bignum
941     type_literal_generic_bignum_symbol(column)
942   else
943     type_literal_specific(column)
944   end
945 end
type_literal_generic(column) click to toggle source

SQL fragment specifying the full type of a column, consider the type with possible modifiers.

    # File lib/sequel/database/schema_methods.rb
949 def type_literal_generic(column)
950   meth = "type_literal_generic_#{column[:type].name.to_s.downcase}"
951   if respond_to?(meth, true)
952     # Allow calling private methods as per type literal generic methods are private
953     send(meth, column)
954   else
955     raise Error, "Unsupported ruby class used as database type: #{column[:type]}"
956   end
957 end
type_literal_generic_bigdecimal(column) click to toggle source

Alias for type_literal_generic_numeric, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
960 def type_literal_generic_bigdecimal(column)
961   type_literal_generic_numeric(column)
962 end
type_literal_generic_bignum_symbol(column) click to toggle source

Sequel uses the bigint type by default for :Bignum symbol.

    # File lib/sequel/database/schema_methods.rb
965 def type_literal_generic_bignum_symbol(column)
966   :bigint
967 end
type_literal_generic_date(column) click to toggle source

Sequel uses the date type by default for Dates.

    # File lib/sequel/database/schema_methods.rb
970 def type_literal_generic_date(column)
971   :date
972 end
type_literal_generic_datetime(column) click to toggle source

Sequel uses the timestamp type by default for DateTimes.

    # File lib/sequel/database/schema_methods.rb
975 def type_literal_generic_datetime(column)
976   :timestamp
977 end
type_literal_generic_falseclass(column) click to toggle source

Alias for type_literal_generic_trueclass, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
980 def type_literal_generic_falseclass(column)
981   type_literal_generic_trueclass(column)
982 end
type_literal_generic_file(column) click to toggle source

Sequel uses the blob type by default for Files.

    # File lib/sequel/database/schema_methods.rb
985 def type_literal_generic_file(column)
986   :blob
987 end
type_literal_generic_fixnum(column) click to toggle source

Alias for type_literal_generic_integer, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
990 def type_literal_generic_fixnum(column)
991   type_literal_generic_integer(column)
992 end
type_literal_generic_float(column) click to toggle source

Sequel uses the double precision type by default for Floats.

    # File lib/sequel/database/schema_methods.rb
995 def type_literal_generic_float(column)
996   :"double precision"
997 end
type_literal_generic_integer(column) click to toggle source

Sequel uses the integer type by default for integers

     # File lib/sequel/database/schema_methods.rb
1000 def type_literal_generic_integer(column)
1001   :integer
1002 end
type_literal_generic_numeric(column) click to toggle source

Sequel uses the numeric type by default for Numerics and BigDecimals. If a size is given, it is used, otherwise, it will default to whatever the database default is for an unsized value.

     # File lib/sequel/database/schema_methods.rb
1007 def type_literal_generic_numeric(column)
1008   column[:size] ? "numeric(#{Array(column[:size]).join(', ')})" : :numeric
1009 end
type_literal_generic_only_time(column) click to toggle source

Use time by default for Time values if :only_time option is used.

     # File lib/sequel/database/schema_methods.rb
1036 def type_literal_generic_only_time(column)
1037   :time
1038 end
type_literal_generic_string(column) click to toggle source

Sequel uses the varchar type by default for Strings. If a size isn't present, Sequel assumes a size of 255. If the :fixed option is used, Sequel uses the char type. If the :text option is used, Sequel uses the :text type.

     # File lib/sequel/database/schema_methods.rb
1015 def type_literal_generic_string(column)
1016   if column[:text]
1017     uses_clob_for_text? ? :clob : :text
1018   elsif column[:fixed]
1019     "char(#{column[:size]||default_string_column_size})"
1020   else
1021     "varchar(#{column[:size]||default_string_column_size})"
1022   end
1023 end
type_literal_generic_time(column) click to toggle source

Sequel uses the timestamp type by default for Time values. If the :only_time option is used, the time type is used.

     # File lib/sequel/database/schema_methods.rb
1027 def type_literal_generic_time(column)
1028   if column[:only_time]
1029     type_literal_generic_only_time(column)
1030   else
1031     type_literal_generic_datetime(column)
1032   end
1033 end
type_literal_generic_trueclass(column) click to toggle source

Sequel uses the boolean type by default for TrueClass and FalseClass.

     # File lib/sequel/database/schema_methods.rb
1041 def type_literal_generic_trueclass(column)
1042   :boolean
1043 end
type_literal_specific(column) click to toggle source

SQL fragment for the given type of a column if the column is not one of the generic types specified with a ruby class.

     # File lib/sequel/database/schema_methods.rb
1047 def type_literal_specific(column)
1048   type = column[:type]
1049   type = "double precision" if type.to_s == 'double'
1050   column[:size] ||= default_string_column_size if type.to_s == 'varchar'
1051   elements = column[:size] || column[:elements]
1052   "#{type}#{literal(Array(elements)) if elements}#{' UNSIGNED' if column[:unsigned]}"
1053 end
unique_constraint_sql_fragment(_) click to toggle source

Add fragment for unique specification, separated for easier overridding.

     # File lib/sequel/database/schema_methods.rb
1056 def unique_constraint_sql_fragment(_)
1057   'UNIQUE'
1058 end
uses_clob_for_text?() click to toggle source

Whether clob should be used for String text: true columns.

     # File lib/sequel/database/schema_methods.rb
1061 def uses_clob_for_text?
1062   false
1063 end

3 - Methods that create datasets

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Public Instance Methods

[](*args) click to toggle source

Returns a dataset for the database. If the first argument is a string, the method acts as an alias for Database#fetch, returning a dataset for arbitrary SQL, with or without placeholders:

DB['SELECT * FROM items'].all
DB['SELECT * FROM items WHERE name = ?', my_name].all

Otherwise, acts as an alias for Database#from, setting the primary table for the dataset:

DB[:items].sql #=> "SELECT * FROM items"
   # File lib/sequel/database/dataset.rb
21 def [](*args)
22   args.first.is_a?(String) ? fetch(*args) : from(*args)
23 end
dataset() click to toggle source

Returns a blank dataset for this database.

DB.dataset # SELECT *
DB.dataset.from(:items) # SELECT * FROM items
   # File lib/sequel/database/dataset.rb
29 def dataset
30   @dataset_class.new(self)
31 end
fetch(sql, *args, &block) click to toggle source

Fetches records for an arbitrary SQL statement. If a block is given, it is used to iterate over the records:

DB.fetch('SELECT * FROM items'){|r| p r}

The fetch method returns a dataset instance:

DB.fetch('SELECT * FROM items').all

fetch can also perform parameterized queries for protection against SQL injection:

DB.fetch('SELECT * FROM items WHERE name = ?', my_name).all

See caveats listed in Dataset#with_sql regarding datasets using custom SQL and the methods that can be called on them.

   # File lib/sequel/database/dataset.rb
49 def fetch(sql, *args, &block)
50   ds = @default_dataset.with_sql(sql, *args)
51   ds.each(&block) if block
52   ds
53 end
from(*args, &block) click to toggle source

Returns a new dataset with the from method invoked. If a block is given, it acts as a virtual row block

DB.from(:items) # SELECT * FROM items
DB.from{schema[:table]} # SELECT * FROM schema.table
   # File lib/sequel/database/dataset.rb
60 def from(*args, &block)
61   if block
62     @default_dataset.from(*args, &block)
63   elsif args.length == 1 && (table = args[0]).is_a?(Symbol)
64     @default_dataset.send(:cached_dataset, :"_from_#{table}_ds"){@default_dataset.from(table)}
65   else
66     @default_dataset.from(*args)
67   end
68 end
select(*args, &block) click to toggle source

Returns a new dataset with the select method invoked.

DB.select(1) # SELECT 1
DB.select{server_version.function} # SELECT server_version()
DB.select(:id).from(:items) # SELECT id FROM items
   # File lib/sequel/database/dataset.rb
75 def select(*args, &block)
76   @default_dataset.select(*args, &block)
77 end

4 - Methods relating to adapters, connecting, disconnecting, and sharding

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Constants

ADAPTERS

Array of supported database adapters

Attributes

pool[R]

The connection pool for this Database instance. All Database instances have their own connection pools.

Public Class Methods

adapter_class(scheme) click to toggle source

The Database subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.

   # File lib/sequel/database/connecting.rb
16 def self.adapter_class(scheme)
17   scheme.is_a?(Class) ? scheme : load_adapter(scheme.to_sym)
18 end
adapter_scheme() click to toggle source

Returns the scheme symbol for the Database class.

   # File lib/sequel/database/connecting.rb
21 def self.adapter_scheme
22   @scheme
23 end
connect(conn_string, opts = OPTS) { |db| ... } click to toggle source

Connects to a database. See Sequel.connect.

   # File lib/sequel/database/connecting.rb
26 def self.connect(conn_string, opts = OPTS)
27   case conn_string
28   when String
29     if conn_string.start_with?('jdbc:')
30       c = adapter_class(:jdbc)
31       opts = opts.merge(:orig_opts=>opts.dup)
32       opts = {:uri=>conn_string}.merge!(opts)
33     else
34       uri = URI.parse(conn_string)
35       scheme = uri.scheme
36       c = adapter_class(scheme)
37       uri_options = c.send(:uri_to_options, uri)
38       uri.query.split('&').map{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty?
39       uri_options.to_a.each{|k,v| uri_options[k] = URI::DEFAULT_PARSER.unescape(v) if v.is_a?(String)}
40       opts = uri_options.merge(opts).merge!(:orig_opts=>opts.dup, :uri=>conn_string, :adapter=>scheme)
41     end
42   when Hash
43     opts = conn_string.merge(opts)
44     opts = opts.merge(:orig_opts=>opts.dup)
45     c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter'])
46   else
47     raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}"
48   end
49 
50   opts = opts.inject({}) do |m, (k,v)|
51     k = :user if k.to_s == 'username'
52     m[k.to_sym] = v
53     m
54   end
55 
56   begin
57     db = c.new(opts)
58     if block_given?
59       return yield(db)
60     end
61   ensure
62     if block_given?
63       db.disconnect if db
64       Sequel.synchronize{::Sequel::DATABASES.delete(db)}
65     end
66   end
67   db
68 end
load_adapter(scheme, opts=OPTS) click to toggle source

Load the adapter from the file system. Raises Sequel::AdapterNotFound if the adapter cannot be loaded, or if the adapter isn't registered correctly after being loaded. Options:

:map

The Hash in which to look for an already loaded adapter (defaults to ADAPTER_MAP).

:subdir

The subdirectory of sequel/adapters to look in, only to be used for loading subadapters.

    # File lib/sequel/database/connecting.rb
 76 def self.load_adapter(scheme, opts=OPTS)
 77   map = opts[:map] || ADAPTER_MAP
 78   if subdir = opts[:subdir]
 79     file = "#{subdir}/#{scheme}"
 80   else
 81     file = scheme
 82   end
 83   
 84   unless obj = Sequel.synchronize{map[scheme]}
 85     # attempt to load the adapter file
 86     begin
 87       require "sequel/adapters/#{file}"
 88     rescue LoadError => e
 89       # If subadapter file doesn't exist, just return,
 90       # using the main adapter class without database customizations.
 91       return if subdir
 92       raise Sequel.convert_exception_class(e, AdapterNotFound)
 93     end
 94     
 95     # make sure we actually loaded the adapter
 96     unless obj = Sequel.synchronize{map[scheme]}
 97       raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP"
 98     end
 99   end
100 
101   obj
102 end
set_shared_adapter_scheme(scheme, mod) click to toggle source

Sets the given module as the shared adapter module for the given scheme. Used to register shared adapters for use by the mock adapter. Example:

# in file sequel/adapters/shared/mydb.rb
module Sequel::MyDB
  Sequel::Database.set_shared_adapter_scheme :mydb, self

  def self.mock_adapter_setup(db)
    # ...
  end

  module DatabaseMethods
    # ...
  end

  module DatasetMethods
    # ...
  end
end

would allow the mock adapter to return a Database instance that supports the MyDB syntax via:

Sequel.connect('mock://mydb')
    # File lib/sequel/database/connecting.rb
146 def self.set_shared_adapter_scheme(scheme, mod)
147   Sequel.synchronize{SHARED_ADAPTER_MAP[scheme] = mod}
148 end

Public Instance Methods

adapter_scheme() click to toggle source

Returns the scheme symbol for this instance's class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.

Sequel.connect('jdbc:postgres://...').adapter_scheme
# => :jdbc
    # File lib/sequel/database/connecting.rb
161 def adapter_scheme
162   self.class.adapter_scheme
163 end
add_servers(servers) click to toggle source

Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Only usable when using a sharded connection pool.

servers argument should be a hash with server name symbol keys and hash or proc values. If a servers key is already in use, it's value is overridden with the value provided.

DB.add_servers(f: {host: "hash_host_f"})
    # File lib/sequel/database/connecting.rb
173 def add_servers(servers)
174   unless sharded?
175     raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool"
176   end
177 
178   h = @opts[:servers]
179   Sequel.synchronize{h.merge!(servers)}
180   @pool.add_servers(servers.keys)
181 end
database_type() click to toggle source

The database type for this database object, the same as the adapter scheme by default. Should be overridden in adapters (especially shared adapters) to be the correct type, so that even if two separate Database objects are using different adapters you can tell that they are using the same database type. Even better, you can tell that two Database objects that are using the same adapter are connecting to different database types.

Sequel.connect('jdbc:postgres://...').database_type
# => :postgres
    # File lib/sequel/database/connecting.rb
192 def database_type
193   adapter_scheme
194 end
disconnect(opts = OPTS) click to toggle source

Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:

:server

Should be a symbol specifing the server to disconnect from,

or an array of symbols to specify multiple servers.

Example:

DB.disconnect # All servers
DB.disconnect(server: :server1) # Single server
DB.disconnect(server: [:server1, :server2]) # Multiple servers
    # File lib/sequel/database/connecting.rb
206 def disconnect(opts = OPTS)
207   pool.disconnect(opts)
208 end
disconnect_connection(conn) click to toggle source

Should only be called by the connection pool code to disconnect a connection. By default, calls the close method on the connection object, since most adapters use that, but should be overwritten on other adapters.

    # File lib/sequel/database/connecting.rb
213 def disconnect_connection(conn)
214   conn.close
215 end
remove_servers(*servers) click to toggle source

Dynamically remove existing servers from the connection pool. Only usable when using a sharded connection pool

servers should be symbols or arrays of symbols. If a nonexistent server is specified, it is ignored. If no servers have been specified for this database, no changes are made. If you attempt to remove the :default server, an error will be raised.

DB.remove_servers(:f1, :f2)
    # File lib/sequel/database/connecting.rb
226 def remove_servers(*servers)
227   unless sharded?
228     raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool"
229   end
230 
231   h = @opts[:servers]
232   servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}}
233   @pool.remove_servers(servers)
234 end
servers() click to toggle source

An array of servers/shards for this Database object.

DB.servers # Unsharded: => [:default]
DB.servers # Sharded:   => [:default, :server1, :server2]
    # File lib/sequel/database/connecting.rb
240 def servers
241   pool.servers
242 end
single_threaded?() click to toggle source

Returns true if the database is using a single-threaded connection pool.

    # File lib/sequel/database/connecting.rb
245 def single_threaded?
246   @single_threaded
247 end
synchronize(server=nil) { |conn| ... } click to toggle source

:nocov:

    # File lib/sequel/database/connecting.rb
251 def synchronize(server=nil)
252   @pool.hold(server || :default){|conn| yield conn}
253 end
test_connection(server=nil) click to toggle source

Attempts to acquire a database connection. Returns true if successful. Will probably raise an Error if unsuccessful. If a server argument is given, attempts to acquire a database connection to the given server/shard.

    # File lib/sequel/database/connecting.rb
277 def test_connection(server=nil)
278   synchronize(server){|conn|}
279   true
280 end
valid_connection?(conn) click to toggle source

Check whether the given connection is currently valid, by running a query against it. If the query fails, the connection should probably be removed from the connection pool.

    # File lib/sequel/database/connecting.rb
286 def valid_connection?(conn)
287   sql = valid_connection_sql
288   begin
289     log_connection_execute(conn, sql)
290   rescue Sequel::DatabaseError, *database_error_classes
291     false
292   else
293     true
294   end
295 end

Private Instance Methods

connection_pool_default_options() click to toggle source

The default options for the connection pool.

    # File lib/sequel/database/connecting.rb
300 def connection_pool_default_options
301   {}
302 end
server_opts(server) click to toggle source

Return the options for the given server by merging the generic options for all server with the specific options for the given server specified in the :servers option.

    # File lib/sequel/database/connecting.rb
307 def server_opts(server)
308   opts = if @opts[:servers] and server_options = @opts[:servers][server]
309     case server_options
310     when Hash
311       @opts.merge(server_options)
312     when Proc
313       @opts.merge(server_options.call(self))
314     else
315       raise Error, 'Server opts should be a hash or proc'
316     end
317   elsif server.is_a?(Hash)
318     @opts.merge(server)
319   else
320     @opts.dup
321   end
322   opts.delete(:servers)
323   opts
324 end
valid_connection_sql() click to toggle source

The SQL query to issue to check if a connection is valid.

    # File lib/sequel/database/connecting.rb
327 def valid_connection_sql
328   @valid_connection_sql ||= select(nil).sql
329 end

5 - Methods that set defaults for created datasets

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Attributes

dataset_class[R]

The class to use for creating datasets. Should respond to new with the Database argument as the first argument, and an optional options hash.

Public Instance Methods

dataset_class=(c) click to toggle source

If the database has any dataset modules associated with it, use a subclass of the given class that includes the modules as the dataset class.

   # File lib/sequel/database/dataset_defaults.rb
18 def dataset_class=(c)
19   unless @dataset_modules.empty?
20     c = Class.new(c)
21     @dataset_modules.each{|m| c.send(:include, m)}
22   end
23   @dataset_class = c
24   reset_default_dataset
25 end
extend_datasets(mod=nil, &block) click to toggle source

Equivalent to extending all datasets produced by the database with a module. What it actually does is use a subclass of the current dataset_class as the new dataset_class, and include the module in the subclass. Instead of a module, you can provide a block that is used to create an anonymous module.

This allows you to override any of the dataset methods even if they are defined directly on the dataset class that this Database object uses.

If a block is given, a Dataset::DatasetModule instance is created, allowing for the easy creation of named dataset methods that will do caching.

Examples:

# Introspect columns for all of DB's datasets
DB.extend_datasets(Sequel::ColumnsIntrospection)

# Trace all SELECT queries by printing the SQL and the full backtrace
DB.extend_datasets do
  def fetch_rows(sql)
    puts sql
    puts caller
    super
  end
end

# Add some named dataset methods
DB.extend_datasets do
  order :by_id, :id
  select :with_id_and_name, :id, :name
  where :active, :active
end

DB[:table].active.with_id_and_name.by_id
# SELECT id, name FROM table WHERE active ORDER BY id
   # File lib/sequel/database/dataset_defaults.rb
62 def extend_datasets(mod=nil, &block)
63   raise(Error, "must provide either mod or block, not both") if mod && block
64   mod = Dataset::DatasetModule.new(&block) if block
65   if @dataset_modules.empty?
66    @dataset_modules = [mod]
67    @dataset_class = Class.new(@dataset_class)
68   else
69    @dataset_modules << mod
70   end
71   @dataset_class.send(:include, mod)
72   reset_default_dataset
73 end

Private Instance Methods

dataset_class_default() click to toggle source

The default dataset class to use for the database

   # File lib/sequel/database/dataset_defaults.rb
78 def dataset_class_default
79   Sequel::Dataset
80 end
quote_identifiers_default() click to toggle source

Whether to quote identifiers by default for this database, true by default.

   # File lib/sequel/database/dataset_defaults.rb
89 def quote_identifiers_default
90   true
91 end
reset_default_dataset() click to toggle source

Reset the default dataset used by most Database methods that create datasets.

   # File lib/sequel/database/dataset_defaults.rb
83 def reset_default_dataset
84   Sequel.synchronize{@symbol_literal_cache.clear}
85   @default_dataset = dataset
86 end

6 - Methods relating to logging

↑ top

Attributes

log_connection_info[RW]

Whether to include information about the connection in use when logging queries.

log_warn_duration[RW]

Numeric specifying the duration beyond which queries are logged at warn level instead of info level.

loggers[RW]

Array of SQL loggers to use for this database.

sql_log_level[RW]

Log level at which to log SQL queries. This is actually the method sent to the logger, so it should be the method name symbol. The default is :info, it can be set to :debug to log at DEBUG level.

Public Instance Methods

log_connection_yield(sql, conn, args=nil) { || ... } click to toggle source

Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.

   # File lib/sequel/database/logging.rb
37 def log_connection_yield(sql, conn, args=nil)
38   return yield if skip_logging?
39   sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}"
40   timer = Sequel.start_timer
41 
42   begin
43     yield
44   rescue => e
45     log_exception(e, sql)
46     raise
47   ensure
48     log_duration(Sequel.elapsed_seconds_since(timer), sql) unless e
49   end
50 end
log_exception(exception, message) click to toggle source

Log a message at error level, with information about the exception.

   # File lib/sequel/database/logging.rb
26 def log_exception(exception, message)
27   log_each(:error, "#{exception.class}: #{exception.message.strip if exception.message}: #{message}")
28 end
log_info(message, args=nil) click to toggle source

Log a message at level info to all loggers.

   # File lib/sequel/database/logging.rb
31 def log_info(message, args=nil)
32   log_each(:info, args ? "#{message}; #{args.inspect}" : message)
33 end
logger=(logger) click to toggle source

Remove any existing loggers and just use the given logger:

DB.logger = Logger.new($stdout)
   # File lib/sequel/database/logging.rb
55 def logger=(logger)
56   @loggers = Array(logger)
57 end

Private Instance Methods

connection_info(conn) click to toggle source

String including information about the connection, for use when logging connection info.

   # File lib/sequel/database/logging.rb
69 def connection_info(conn)
70   "(conn: #{conn.__id__}) "
71 end
log_connection_execute(conn, sql) click to toggle source

Log the given SQL and then execute it on the connection, used by the transaction code.

   # File lib/sequel/database/logging.rb
75 def log_connection_execute(conn, sql)
76   log_connection_yield(sql, conn){conn.public_send(connection_execute_method, sql)}
77 end
log_duration(duration, message) click to toggle source

Log message with message prefixed by duration at info level, or warn level if duration is greater than log_warn_duration.

   # File lib/sequel/database/logging.rb
81 def log_duration(duration, message)
82   log_each((lwd = log_warn_duration and duration >= lwd) ? :warn : sql_log_level, "(#{sprintf('%0.6fs', duration)}) #{message}")
83 end
log_each(level, message) click to toggle source

Log message at level (which should be :error, :warn, or :info) to all loggers.

   # File lib/sequel/database/logging.rb
87 def log_each(level, message)
88   @loggers.each{|logger| logger.public_send(level, message)}
89 end
skip_logging?() click to toggle source

Determine if logging should be skipped. Defaults to true if no loggers have been specified.

   # File lib/sequel/database/logging.rb
63 def skip_logging?
64   @loggers.empty?
65 end

7 - Miscellaneous methods

↑ top

Constants

CHECK_CONSTRAINT_SQLSTATES
DEFAULT_DATABASE_ERROR_REGEXPS

Empty exception regexp to class map, used by default if Sequel doesn't have specific support for the database in use.

DEFAULT_STRING_COLUMN_SIZE

The general default size for string columns for all Sequel::Database instances.

EXTENSIONS

Hash of extension name symbols to callable objects to load the extension into the Database object (usually by extending it with a module defined in the extension).

FOREIGN_KEY_CONSTRAINT_SQLSTATES
NOT_NULL_CONSTRAINT_SQLSTATES
SCHEMA_TYPE_CLASSES

Mapping of schema type symbols to class or arrays of classes for that symbol.

SERIALIZATION_CONSTRAINT_SQLSTATES
UNIQUE_CONSTRAINT_SQLSTATES

Attributes

default_string_column_size[RW]

The specific default size of string columns for this Sequel::Database, usually 255 by default.

opts[R]

The options hash for this database

timezone[W]

Set the timezone to use for this database, overridding Sequel.database_timezone.

Public Class Methods

after_initialize(&block) click to toggle source

Register a hook that will be run when a new Database is instantiated. It is called with the new database handle.

   # File lib/sequel/database/misc.rb
34 def self.after_initialize(&block)
35   raise Error, "must provide block to after_initialize" unless block
36   Sequel.synchronize do
37     previous = @initialize_hook
38     @initialize_hook = proc do |db|
39       previous.call(db)
40       block.call(db)
41     end
42   end
43 end
extension(*extensions) click to toggle source

Apply an extension to all Database objects created in the future.

   # File lib/sequel/database/misc.rb
46 def self.extension(*extensions)
47   after_initialize{|db| db.extension(*extensions)}
48 end
new(opts = OPTS) click to toggle source

Constructs a new instance of a database connection with the specified options hash.

Accepts the following options:

:cache_schema

Whether schema should be cached for this Database instance

:default_string_column_size

The default size of string columns, 255 by default.

:extensions

Extensions to load into this Database instance. Can be a symbol, array of symbols, or string with extensions separated by columns. These extensions are loaded after connections are made by the :preconnect option.

:keep_reference

Whether to keep a reference to this instance in Sequel::DATABASES, true by default.

:logger

A specific logger to use.

:loggers

An array of loggers to use.

:log_connection_info

Whether connection information should be logged when logging queries.

:log_warn_duration

The number of elapsed seconds after which queries should be logged at warn level.

:name

A name to use for the Database object, displayed in PoolTimeout .

:preconnect

Automatically create the maximum number of connections, so that they don't need to be created as needed. This is useful when connecting takes a long time and you want to avoid possible latency during runtime. Set to :concurrently to create the connections in separate threads. Otherwise they'll be created sequentially.

:preconnect_extensions

Similar to the :extensions option, but loads the extensions before the connections are made by the :preconnect option.

:quote_identifiers

Whether to quote identifiers.

:servers

A hash specifying a server/shard specific options, keyed by shard symbol .

:single_threaded

Whether to use a single-threaded connection pool.

:sql_log_level

Method to use to log SQL to a logger, :info by default.

All options given are also passed to the connection pool. Additional options respected by the connection pool are :after_connect, :connect_sqls, :max_connections, :pool_timeout, :servers, and :servers_hash. See the connection pool documentation for details.

    # File lib/sequel/database/misc.rb
124 def initialize(opts = OPTS)
125   @opts ||= opts
126   @opts = connection_pool_default_options.merge(@opts)
127   @loggers = Array(@opts[:logger]) + Array(@opts[:loggers])
128   @opts[:servers] = {} if @opts[:servers].is_a?(String)
129   @sharded = !!@opts[:servers]
130   @opts[:adapter_class] = self.class
131   @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded))
132   @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE
133 
134   @schemas = {}
135   @prepared_statements = {}
136   @transactions = {}
137   @symbol_literal_cache = {}
138 
139   @timezone = nil
140 
141   @dataset_class = dataset_class_default
142   @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true))
143   @dataset_modules = []
144   @loaded_extensions = []
145   @schema_type_classes = SCHEMA_TYPE_CLASSES.dup
146 
147   self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info
148   self.log_warn_duration = @opts[:log_warn_duration]
149   self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info])
150 
151   @pool = ConnectionPool.get_pool(self, @opts)
152 
153   reset_default_dataset
154   adapter_initialize
155 
156   keep_reference = typecast_value_boolean(@opts[:keep_reference]) != false
157   begin
158     Sequel.synchronize{::Sequel::DATABASES.push(self)} if keep_reference
159     Sequel::Database.run_after_initialize(self)
160 
161     initialize_load_extensions(:preconnect_extensions)
162 
163     if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true)
164       concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently"
165       @pool.send(:preconnect, concurrent)
166     end
167 
168     initialize_load_extensions(:extensions)
169     test_connection if typecast_value_boolean(@opts.fetch(:test, true)) && respond_to?(:connect, true)
170   rescue
171     Sequel.synchronize{::Sequel::DATABASES.delete(self)} if keep_reference
172     raise
173   end
174 end
register_extension(ext, mod=nil, &block) click to toggle source

Register an extension callback for Database objects. ext should be the extension name symbol, and mod should either be a Module that the database is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.

   # File lib/sequel/database/misc.rb
55 def self.register_extension(ext, mod=nil, &block)
56   if mod
57     raise(Error, "cannot provide both mod and block to Database.register_extension") if block
58     if mod.is_a?(Module)
59       block = proc{|db| db.extend(mod)}
60     else
61       block = mod
62     end
63   end
64   Sequel.synchronize{EXTENSIONS[ext] = block}
65 end
run_after_initialize(instance) click to toggle source

Run the after_initialize hook for the given instance.

   # File lib/sequel/database/misc.rb
68 def self.run_after_initialize(instance)
69   @initialize_hook.call(instance)
70 end

Private Class Methods

uri_to_options(uri) click to toggle source

Converts a uri to an options hash. These options are then passed to a newly created database object.

   # File lib/sequel/database/misc.rb
74 def self.uri_to_options(uri)
75   {
76     :user => uri.user,
77     :password => uri.password,
78     :port => uri.port,
79     :host => uri.hostname,
80     :database => (m = /\/(.*)/.match(uri.path)) && (m[1])
81   }
82 end

Public Instance Methods

cast_type_literal(type) click to toggle source

Cast the given type to a literal type

DB.cast_type_literal(Float) # double precision
DB.cast_type_literal(:foo)  # foo
    # File lib/sequel/database/misc.rb
203 def cast_type_literal(type)
204   type_literal(:type=>type)
205 end
extension(*exts) click to toggle source

Load an extension into the receiver. In addition to requiring the extension file, this also modifies the database to work with the extension (usually extending it with a module defined in the extension file). If no related extension file exists or the extension does not have specific support for Database objects, an Error will be raised. Returns self.

    # File lib/sequel/database/misc.rb
212 def extension(*exts)
213   Sequel.extension(*exts)
214   exts.each do |ext|
215     if pr = Sequel.synchronize{EXTENSIONS[ext]}
216       unless Sequel.synchronize{@loaded_extensions.include?(ext)}
217         Sequel.synchronize{@loaded_extensions << ext}
218         pr.call(self)
219       end
220     else
221       raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})")
222     end
223   end
224   self
225 end
freeze() click to toggle source

Freeze internal data structures for the Database instance.

Calls superclass method
    # File lib/sequel/database/misc.rb
177 def freeze
178   valid_connection_sql
179   metadata_dataset
180   @opts.freeze
181   @loggers.freeze
182   @pool.freeze
183   @dataset_class.freeze
184   @dataset_modules.freeze
185   @schema_type_classes.freeze
186   @loaded_extensions.freeze
187   metadata_dataset
188   super
189 end
from_application_timestamp(v) click to toggle source

Convert the given timestamp from the application's timezone, to the databases's timezone or the default database timezone if the database does not have a timezone.

    # File lib/sequel/database/misc.rb
230 def from_application_timestamp(v)
231   Sequel.convert_output_timestamp(v, timezone)
232 end
inspect() click to toggle source

Returns a string representation of the database object including the class name and connection URI and options used when connecting (if any).

    # File lib/sequel/database/misc.rb
236 def inspect
237   a = []
238   a << uri.inspect if uri
239   if (oo = opts[:orig_opts]) && !oo.empty?
240     a << oo.inspect
241   end
242   "#<#{self.class}: #{a.join(' ')}>"
243 end
literal(v) click to toggle source

Proxy the literal call to the dataset.

DB.literal(1)   # 1
DB.literal(:a)  # a
DB.literal('a') # 'a'
    # File lib/sequel/database/misc.rb
250 def literal(v)
251   schema_utility_dataset.literal(v)
252 end
literal_symbol(sym) click to toggle source

Return the literalized version of the symbol if cached, or nil if it is not cached.

    # File lib/sequel/database/misc.rb
256 def literal_symbol(sym)
257   Sequel.synchronize{@symbol_literal_cache[sym]}
258 end
literal_symbol_set(sym, lit) click to toggle source

Set the cached value of the literal symbol.

    # File lib/sequel/database/misc.rb
261 def literal_symbol_set(sym, lit)
262   Sequel.synchronize{@symbol_literal_cache[sym] = lit}
263 end
prepared_statement(name) click to toggle source

Synchronize access to the prepared statements cache.

    # File lib/sequel/database/misc.rb
266 def prepared_statement(name)
267   Sequel.synchronize{prepared_statements[name]}
268 end
quote_identifier(v) click to toggle source

Proxy the quote_identifier method to the dataset, useful for quoting unqualified identifiers for use outside of datasets.

    # File lib/sequel/database/misc.rb
273 def quote_identifier(v)
274   schema_utility_dataset.quote_identifier(v)
275 end
schema_type_class(type) click to toggle source

Return ruby class or array of classes for the given type symbol.

    # File lib/sequel/database/misc.rb
278 def schema_type_class(type)
279   @schema_type_classes[type]
280 end
serial_primary_key_options() click to toggle source

Default serial primary key options, used by the table creation code.

    # File lib/sequel/database/misc.rb
283 def serial_primary_key_options
284   {:primary_key => true, :type => Integer, :auto_increment => true}
285 end
set_prepared_statement(name, ps) click to toggle source

Cache the prepared statement object at the given name.

    # File lib/sequel/database/misc.rb
288 def set_prepared_statement(name, ps)
289   Sequel.synchronize{prepared_statements[name] = ps}
290 end
sharded?() click to toggle source

Whether this database instance uses multiple servers, either for sharding or for primary/replica configurations.

    # File lib/sequel/database/misc.rb
294 def sharded?
295   @sharded
296 end
timezone() click to toggle source

The timezone to use for this database, defaulting to Sequel.database_timezone.

    # File lib/sequel/database/misc.rb
299 def timezone
300   @timezone || Sequel.database_timezone
301 end
to_application_timestamp(v) click to toggle source

Convert the given timestamp to the application's timezone, from the databases's timezone or the default database timezone if the database does not have a timezone.

    # File lib/sequel/database/misc.rb
306 def to_application_timestamp(v)
307   Sequel.convert_timestamp(v, timezone)
308 end
typecast_value(column_type, value) click to toggle source

Typecast the value to the given column_type. Calls typecast_value_#{column_type} if the method exists, otherwise returns the value. This method should raise Sequel::InvalidValue if assigned value is invalid.

    # File lib/sequel/database/misc.rb
315 def typecast_value(column_type, value)
316   return nil if value.nil?
317   meth = "typecast_value_#{column_type}"
318   begin
319     # Allow calling private methods as per-type typecasting methods are private
320     respond_to?(meth, true) ? send(meth, value) : value
321   rescue ArgumentError, TypeError => e
322     raise Sequel.convert_exception_class(e, InvalidValue)
323   end
324 end
uri() click to toggle source

Returns the URI use to connect to the database. If a URI was not used when connecting, returns nil.

    # File lib/sequel/database/misc.rb
328 def uri
329   opts[:uri]
330 end
url() click to toggle source

Explicit alias of uri for easier subclassing.

    # File lib/sequel/database/misc.rb
333 def url
334   uri
335 end

Private Instance Methods

_typecast_value_string_to_decimal(value) click to toggle source

:nocov:

    # File lib/sequel/database/misc.rb
504 def _typecast_value_string_to_decimal(value)
505   d = BigDecimal(value)
506   if d.zero?
507     # BigDecimal parsing is loose by default, returning a 0 value for
508     # invalid input.  If a zero value is received, use Float to check
509     # for validity.
510     begin
511       Float(value)
512     rescue ArgumentError
513       raise InvalidValue, "invalid value for BigDecimal: #{value.inspect}"
514     end
515   end
516   d
517 end
adapter_initialize() click to toggle source

Per adapter initialization method, empty by default.

    # File lib/sequel/database/misc.rb
340 def adapter_initialize
341 end
blank_object?(obj) click to toggle source

Returns true when the object is considered blank. The only objects that are blank are nil, false, strings with all whitespace, and ones that respond true to empty?

    # File lib/sequel/database/misc.rb
347 def blank_object?(obj)
348   return obj.blank? if obj.respond_to?(:blank?)
349   case obj
350   when NilClass, FalseClass
351     true
352   when Numeric, TrueClass
353     false
354   when String
355     obj.strip.empty?
356   else
357     obj.respond_to?(:empty?) ? obj.empty? : false
358   end
359 end
database_error_class(exception, opts) click to toggle source

Return the Sequel::DatabaseError subclass to wrap the given exception in.

    # File lib/sequel/database/misc.rb
370 def database_error_class(exception, opts)
371   database_specific_error_class(exception, opts) || DatabaseError
372 end
database_error_regexps() click to toggle source

An enumerable yielding pairs of regexps and exception classes, used to match against underlying driver exception messages in order to raise a more specific Sequel::DatabaseError subclass.

    # File lib/sequel/database/misc.rb
364 def database_error_regexps
365   DEFAULT_DATABASE_ERROR_REGEXPS
366 end
database_exception_sqlstate(exception, opts) click to toggle source

Return the SQLState for the given exception, if one can be determined

    # File lib/sequel/database/misc.rb
375 def database_exception_sqlstate(exception, opts)
376   nil
377 end
database_specific_error_class(exception, opts) click to toggle source

Return a specific Sequel::DatabaseError exception class if one is appropriate for the underlying exception, or nil if there is no specific exception class.

    # File lib/sequel/database/misc.rb
382 def database_specific_error_class(exception, opts)
383   return DatabaseDisconnectError if disconnect_error?(exception, opts)
384 
385   if sqlstate = database_exception_sqlstate(exception, opts)
386     if klass = database_specific_error_class_from_sqlstate(sqlstate)
387       return klass
388     end
389   else
390     database_error_regexps.each do |regexp, klss|
391       return klss if exception.message =~ regexp
392     end
393   end
394 
395   nil
396 end
database_specific_error_class_from_sqlstate(sqlstate) click to toggle source

Given the SQLState, return the appropriate DatabaseError subclass.

    # File lib/sequel/database/misc.rb
404 def database_specific_error_class_from_sqlstate(sqlstate)
405   case sqlstate
406   when *NOT_NULL_CONSTRAINT_SQLSTATES
407     NotNullConstraintViolation
408   when *FOREIGN_KEY_CONSTRAINT_SQLSTATES
409     ForeignKeyConstraintViolation
410   when *UNIQUE_CONSTRAINT_SQLSTATES
411     UniqueConstraintViolation
412   when *CHECK_CONSTRAINT_SQLSTATES
413     CheckConstraintViolation
414   when *SERIALIZATION_CONSTRAINT_SQLSTATES
415     SerializationFailure
416   end
417 end
disconnect_error?(exception, opts) click to toggle source

Return true if exception represents a disconnect error, false otherwise.

    # File lib/sequel/database/misc.rb
420 def disconnect_error?(exception, opts)
421   opts[:disconnect]
422 end
initialize_load_extensions(key) click to toggle source

Load extensions during initialization from the given key in opts.

    # File lib/sequel/database/misc.rb
425 def initialize_load_extensions(key)
426   case exts = @opts[key]
427   when String
428     extension(*exts.split(',').map(&:to_sym))
429   when Array
430     extension(*exts)
431   when Symbol
432     extension(exts)
433   when nil
434     # nothing
435   else
436     raise Error, "unsupported Database #{key.inspect} option: #{@opts[key].inspect}"
437   end
438 end
raise_error(exception, opts=OPTS) click to toggle source

Convert the given exception to an appropriate Sequel::DatabaseError subclass, keeping message and backtrace.

    # File lib/sequel/database/misc.rb
442 def raise_error(exception, opts=OPTS)
443   if !opts[:classes] || Array(opts[:classes]).any?{|c| exception.is_a?(c)}
444     raise Sequel.convert_exception_class(exception, database_error_class(exception, opts))
445   else
446     raise exception
447   end
448 end
swallow_database_error() { || ... } click to toggle source

Swallow database errors, unless they are connect/disconnect errors.

    # File lib/sequel/database/misc.rb
451 def swallow_database_error
452   yield
453 rescue Sequel::DatabaseDisconnectError, DatabaseConnectionError
454   # Always raise disconnect errors
455   raise
456 rescue Sequel::DatabaseError
457   # Don't raise other database errors.
458   nil
459 # else
460 #   Don't rescue other exceptions, they will be raised normally.
461 end
typecast_value_blob(value) click to toggle source

Typecast the value to an SQL::Blob

    # File lib/sequel/database/misc.rb
464 def typecast_value_blob(value)
465   value.is_a?(Sequel::SQL::Blob) ? value : Sequel::SQL::Blob.new(value)
466 end
typecast_value_boolean(value) click to toggle source

Typecast the value to true, false, or nil

    # File lib/sequel/database/misc.rb
469 def typecast_value_boolean(value)
470   case value
471   when false, 0, "0", /\Af(alse)?\z/i, /\Ano?\z/i
472     false
473   else
474     blank_object?(value) ? nil : true
475   end
476 end
typecast_value_date(value) click to toggle source

Typecast the value to a Date

    # File lib/sequel/database/misc.rb
479 def typecast_value_date(value)
480   case value
481   when DateTime, Time
482     Date.new(value.year, value.month, value.day)
483   when Date
484     value
485   when String
486     Sequel.string_to_date(value)
487   when Hash
488     Date.new(*[:year, :month, :day].map{|x| (value[x] || value[x.to_s]).to_i})
489   else
490     raise InvalidValue, "invalid value for Date: #{value.inspect}"
491   end
492 end
typecast_value_datetime(value) click to toggle source

Typecast the value to a DateTime or Time depending on Sequel.datetime_class

    # File lib/sequel/database/misc.rb
495 def typecast_value_datetime(value)
496   Sequel.typecast_to_application_timestamp(value)
497 end
typecast_value_decimal(value) click to toggle source

Typecast the value to a BigDecimal

    # File lib/sequel/database/misc.rb
522 def typecast_value_decimal(value)
523   case value
524   when BigDecimal
525     value
526   when Numeric
527     BigDecimal(value.to_s)
528   when String
529     _typecast_value_string_to_decimal(value)
530   else
531     raise InvalidValue, "invalid value for BigDecimal: #{value.inspect}"
532   end
533 end
typecast_value_integer(value) click to toggle source

Typecast the value to an Integer

    # File lib/sequel/database/misc.rb
539 def typecast_value_integer(value)
540   (value.is_a?(String) && value =~ /\A0+(\d)/) ? Integer(value, 10) : Integer(value)
541 end
typecast_value_string(value) click to toggle source

Typecast the value to a String

    # File lib/sequel/database/misc.rb
544 def typecast_value_string(value)
545   case value
546   when Hash, Array
547     raise Sequel::InvalidValue, "invalid value for String: #{value.inspect}"
548   else
549     value.to_s
550   end
551 end
typecast_value_time(value) click to toggle source

Typecast the value to a Time

    # File lib/sequel/database/misc.rb
554 def typecast_value_time(value)
555   case value
556   when Time
557     if value.is_a?(SQLTime)
558       value
559     else
560       SQLTime.create(value.hour, value.min, value.sec, value.nsec/1000.0)
561     end
562   when String
563     Sequel.string_to_time(value)
564   when Hash
565     SQLTime.create(*[:hour, :minute, :second].map{|x| (value[x] || value[x.to_s]).to_i})
566   else
567     raise Sequel::InvalidValue, "invalid value for Time: #{value.inspect}"
568   end
569 end

8 - Methods related to database transactions

↑ top

Constants

TRANSACTION_ISOLATION_LEVELS

Attributes

transaction_isolation_level[RW]

The default transaction isolation level for this database, used for all future transactions. For MSSQL, this should be set to something if you ever plan to use the :isolation option to Database#transaction, as on MSSQL if affects all future transactions on the same connection.

Public Instance Methods

after_commit(opts=OPTS) { || ... } click to toggle source

If a transaction is not currently in process, yield to the block immediately. Otherwise, add the block to the list of blocks to call after the currently in progress transaction commits (and only if it commits). Options:

:savepoint

If currently inside a savepoint, only run this hook on transaction commit if all enclosing savepoints have been released.

:server

The server/shard to use.

   # File lib/sequel/database/transactions.rb
31 def after_commit(opts=OPTS, &block)
32   raise Error, "must provide block to after_commit" unless block
33   synchronize(opts[:server]) do |conn|
34     if h = _trans(conn)
35       raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare]
36       if opts[:savepoint] && in_savepoint?(conn)
37         add_savepoint_hook(conn, :after_commit, block)
38       else
39         add_transaction_hook(conn, :after_commit, block)
40       end
41     else
42       yield
43     end
44   end
45 end
after_rollback(opts=OPTS, &block) click to toggle source

If a transaction is not currently in progress, ignore the block. Otherwise, add the block to the list of the blocks to call after the currently in progress transaction rolls back (and only if it rolls back). Options:

:savepoint

If currently inside a savepoint, run this hook immediately when any enclosing savepoint is rolled back, which may be before the transaction commits or rollsback.

:server

The server/shard to use.

   # File lib/sequel/database/transactions.rb
55 def after_rollback(opts=OPTS, &block)
56   raise Error, "must provide block to after_rollback" unless block
57   synchronize(opts[:server]) do |conn|
58     if h = _trans(conn)
59       raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare]
60       if opts[:savepoint] && in_savepoint?(conn)
61         add_savepoint_hook(conn, :after_rollback, block)
62       else
63         add_transaction_hook(conn, :after_rollback, block)
64       end
65     end
66   end
67 end
in_transaction?(opts=OPTS) click to toggle source

Return true if already in a transaction given the options, false otherwise. Respects the :server option for selecting a shard.

    # File lib/sequel/database/transactions.rb
113 def in_transaction?(opts=OPTS)
114   synchronize(opts[:server]){|conn| !!_trans(conn)}
115 end
rollback_checker(opts=OPTS) click to toggle source

Returns a proc that you can call to check if the transaction has been rolled back. The proc will return nil if the transaction is still in progress, true if the transaction was rolled back, and false if it was committed. Raises an Error if called outside a transaction. Respects the :server option for selecting a shard.

    # File lib/sequel/database/transactions.rb
123 def rollback_checker(opts=OPTS)
124   synchronize(opts[:server]) do |conn|
125     raise Error, "not in a transaction" unless t = _trans(conn)
126     t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}}
127   end
128 end
rollback_on_exit(opts=OPTS) click to toggle source

When exiting the transaction block through methods other than an exception (e.g. normal exit, non-local return, or throw), set the current transaction to rollback instead of committing. This is designed for use in cases where you want to preform a non-local return but also want to rollback instead of committing. Options:

:cancel

Cancel the current rollback_on_exit setting, so exiting will commit instead of rolling back.

:savepoint

Rollback only the current savepoint if inside a savepoint. Can also be an positive integer value to rollback that number of enclosing savepoints, up to and including the transaction itself. If the database does not support savepoints, this option is ignored and the entire transaction is affected.

:server

The server/shard the transaction is being executed on.

    # File lib/sequel/database/transactions.rb
 83 def rollback_on_exit(opts=OPTS)
 84   synchronize(opts[:server]) do |conn|
 85     raise Error, "Cannot call Sequel:: Database#rollback_on_exit unless inside a transaction" unless h = _trans(conn)
 86     rollback = !opts[:cancel]
 87 
 88     if supports_savepoints?
 89       savepoints = h[:savepoints]
 90 
 91       if level = opts[:savepoint]
 92         level = 1 if level == true
 93         raise Error, "invalid :savepoint option to Database#rollback_on_exit: #{level.inspect}" unless level.is_a?(Integer)
 94         raise Error, "cannot pass nonpositive integer (#{level.inspect}) as :savepoint option to Database#rollback_on_exit" if level < 1
 95         level.times do |i|
 96           break unless savepoint = savepoints[-1 - i]
 97           savepoint[:rollback_on_exit] = rollback
 98         end
 99       else
100         savepoints[0][:rollback_on_exit] = rollback
101       end
102     else
103       h[:rollback_on_exit] = rollback
104     end
105   end
106 
107   nil
108 end
transaction(opts=OPTS) { |conn| ... } click to toggle source

Starts a database transaction. When a database transaction is used, either all statements are successful or none of the statements are successful. Note that MySQL MyISAM tables do not support transactions.

The following general options are respected:

:auto_savepoint

Automatically use a savepoint for Database#transaction calls inside this transaction block.

:isolation

The transaction isolation level to use for this transaction, should be :uncommitted, :committed, :repeatable, or :serializable, used if given and the database/adapter supports customizable transaction isolation levels.

:num_retries

The number of times to retry if the :retry_on option is used. The default is 5 times. Can be set to nil to retry indefinitely, but that is not recommended.

:before_retry

Proc to execute before retrying if the :retry_on option is used. Called with two arguments: the number of retry attempts (counting the current one) and the error the last attempt failed with.

:prepare

A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions.

:retry_on

An exception class or array of exception classes for which to automatically retry the transaction. Can only be set if not inside an existing transaction. Note that this should not be used unless the entire transaction block is idempotent, as otherwise it can cause non-idempotent behavior to execute multiple times.

:rollback

Can be set to :reraise to reraise any Sequel::Rollback exceptions raised, or :always to always rollback even if no exceptions occur (useful for testing).

:server

The server to use for the transaction. Set to :default, :read_only, or whatever symbol you used in the connect string when naming your servers.

:savepoint

Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option. If the surrounding transaction uses :auto_savepoint, you can set this to false to not use a savepoint. If the value given for this option is :only, it will only create a savepoint if it is inside a transaction.

PostgreSQL specific options:

:deferrable

(9.1+) If present, set to DEFERRABLE if true or NOT DEFERRABLE if false.

:read_only

If present, set to READ ONLY if true or READ WRITE if false.

:synchronous

if non-nil, set synchronous_commit appropriately. Valid values true, :on, false, :off, :local (9.1+), and :remote_write (9.2+).

    # File lib/sequel/database/transactions.rb
177 def transaction(opts=OPTS, &block)
178   opts = Hash[opts]
179   if retry_on = opts[:retry_on]
180     tot_retries = opts.fetch(:num_retries, 5)
181     num_retries = 0
182     begin
183       opts[:retry_on] = nil
184       opts[:retrying] = true
185       transaction(opts, &block)
186     rescue *retry_on => e
187       num_retries += 1
188       if tot_retries.nil? || num_retries <= tot_retries
189         opts[:before_retry].call(num_retries, e) if opts[:before_retry]
190         retry
191       end
192       raise
193     end
194   else
195     synchronize(opts[:server]) do |conn|
196       if opts[:savepoint] == :only
197         if supports_savepoints?
198           if _trans(conn)
199             opts[:savepoint] = true
200           else
201             return yield(conn)
202           end
203         else
204           opts[:savepoint] = false
205         end
206       end
207 
208       if opts[:savepoint] && !supports_savepoints?
209         raise Sequel::InvalidOperation, "savepoints not supported on #{database_type}"
210       end
211 
212       if already_in_transaction?(conn, opts)
213         if opts[:rollback] == :always && !opts.has_key?(:savepoint)
214           if supports_savepoints? 
215             opts[:savepoint] = true
216           else
217             raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction"
218           end
219         end
220 
221         if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last[:auto_savepoint]
222           opts[:savepoint] = true
223         end
224 
225         unless opts[:savepoint]
226           if opts[:retrying]
227             raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction"
228           end
229           return yield(conn)
230         end
231       end
232 
233       _transaction(conn, opts, &block)
234     end
235   end
236 end

Private Instance Methods

_trans(conn) click to toggle source

Synchronize access to the current transactions, returning the hash of options for the current transaction (if any)

    # File lib/sequel/database/transactions.rb
289 def _trans(conn)
290   Sequel.synchronize{@transactions[conn]}
291 end
_transaction(conn, opts=OPTS) { |conn| ... } click to toggle source

Internal generic transaction method. Any exception raised by the given block will cause the transaction to be rolled back. If the exception is not a Sequel::Rollback, the error will be reraised. If no exception occurs inside the block, the transaction is commited.

    # File lib/sequel/database/transactions.rb
244 def _transaction(conn, opts=OPTS)
245   rollback = opts[:rollback]
246   begin
247     add_transaction(conn, opts)
248     begin_transaction(conn, opts)
249     if rollback == :always
250       begin
251         ret = yield(conn)
252       rescue Exception => e1
253         raise e1
254       ensure
255         raise ::Sequel::Rollback unless e1
256       end
257     else
258       yield(conn)
259     end
260   rescue Exception => e
261     begin
262       rollback_transaction(conn, opts)
263     rescue Exception => e3
264     end
265     transaction_error(e, :conn=>conn, :rollback=>rollback)
266     raise e3 if e3
267     ret
268   ensure
269     begin
270       committed = commit_or_rollback_transaction(e, conn, opts)
271     rescue Exception => e2
272       begin
273         raise_error(e2, :classes=>database_error_classes, :conn=>conn)
274       rescue Sequel::DatabaseError => e4
275         begin
276           rollback_transaction(conn, opts)
277         ensure
278           raise e4
279         end
280       end
281     ensure
282       remove_transaction(conn, committed)
283     end
284   end
285 end
add_savepoint_hook(conn, type, block) click to toggle source

Set the given callable as a hook to be called. Type should be either :after_commit or :after_rollback.

    # File lib/sequel/database/transactions.rb
316 def add_savepoint_hook(conn, type, block)
317   savepoint = _trans(conn)[:savepoints].last
318   (savepoint[type] ||= []) << block
319 end
add_transaction(conn, opts) click to toggle source

Add the current thread to the list of active transactions

    # File lib/sequel/database/transactions.rb
294 def add_transaction(conn, opts)
295   hash = transaction_options(conn, opts)
296 
297   if supports_savepoints?
298     if t = _trans(conn)
299       t[:savepoints].push({:auto_savepoint=>opts[:auto_savepoint]})
300       return
301     else
302       hash[:savepoints] = [{:auto_savepoint=>opts[:auto_savepoint]}]
303       if (prep = opts[:prepare]) && supports_prepared_transactions?
304         hash[:prepare] = prep
305       end
306     end
307   elsif (prep = opts[:prepare]) && supports_prepared_transactions?
308     hash[:prepare] = prep
309   end
310 
311   Sequel.synchronize{@transactions[conn] = hash}
312 end
add_transaction_hook(conn, type, block) click to toggle source

Set the given callable as a hook to be called. Type should be either :after_commit or :after_rollback.

    # File lib/sequel/database/transactions.rb
323 def add_transaction_hook(conn, type, block)
324   hooks = _trans(conn)[type] ||= []
325   hooks << block
326 end
already_in_transaction?(conn, opts) click to toggle source

Whether the given connection is already inside a transaction

    # File lib/sequel/database/transactions.rb
329 def already_in_transaction?(conn, opts)
330   _trans(conn) && (!supports_savepoints? || !opts[:savepoint])
331 end
begin_new_transaction(conn, opts) click to toggle source

Start a new database transaction on the given connection

    # File lib/sequel/database/transactions.rb
350 def begin_new_transaction(conn, opts)
351   log_connection_execute(conn, begin_transaction_sql)
352   set_transaction_isolation(conn, opts)
353 end
begin_savepoint(conn, opts) click to toggle source

Issue query to begin a new savepoint.

    # File lib/sequel/database/transactions.rb
340 def begin_savepoint(conn, opts)
341   log_connection_execute(conn, begin_savepoint_sql(savepoint_level(conn)-1))
342 end
begin_savepoint_sql(depth) click to toggle source

SQL to start a new savepoint

    # File lib/sequel/database/transactions.rb
345 def begin_savepoint_sql(depth)
346   "SAVEPOINT autopoint_#{depth}"
347 end
begin_transaction(conn, opts=OPTS) click to toggle source

Start a new database transaction or a new savepoint on the given connection.

    # File lib/sequel/database/transactions.rb
356 def begin_transaction(conn, opts=OPTS)
357   if in_savepoint?(conn)
358     begin_savepoint(conn, opts)
359   else
360     begin_new_transaction(conn, opts)
361   end
362 end
begin_transaction_sql() click to toggle source

SQL to BEGIN a transaction.

    # File lib/sequel/database/transactions.rb
365 def begin_transaction_sql
366   'BEGIN'
367 end
commit_or_rollback_transaction(exception, conn, opts) click to toggle source

Whether to commit the current transaction. Thread.current.status is checked because Thread#kill skips rescue blocks (so exception would be nil), but the transaction should still be rolled back. On Ruby 1.9 (but not 2.0+), the thread status will still be “run”, so Thread#kill will erroneously commit the transaction, and there isn't a workaround.

    # File lib/sequel/database/transactions.rb
374 def commit_or_rollback_transaction(exception, conn, opts)
375   if exception
376     false
377   else
378     if rollback_on_transaction_exit?(conn, opts)
379       rollback_transaction(conn, opts)
380       false
381     else
382       commit_transaction(conn, opts)
383       true
384     end
385   end
386 end
commit_savepoint_sql(depth) click to toggle source

SQL to commit a savepoint

    # File lib/sequel/database/transactions.rb
389 def commit_savepoint_sql(depth)
390   "RELEASE SAVEPOINT autopoint_#{depth}"
391 end
commit_transaction(conn, opts=OPTS) click to toggle source

Commit the active transaction on the connection

    # File lib/sequel/database/transactions.rb
394 def commit_transaction(conn, opts=OPTS)
395   if supports_savepoints?
396     depth = savepoint_level(conn)
397     log_connection_execute(conn, depth > 1 ? commit_savepoint_sql(depth-1) : commit_transaction_sql)
398   else
399     log_connection_execute(conn, commit_transaction_sql)
400   end
401 end
commit_transaction_sql() click to toggle source

SQL to COMMIT a transaction.

    # File lib/sequel/database/transactions.rb
404 def commit_transaction_sql
405   'COMMIT'
406 end
connection_execute_method() click to toggle source

Method called on the connection object to execute SQL on the database, used by the transaction code.

    # File lib/sequel/database/transactions.rb
410 def connection_execute_method
411   :execute
412 end
database_error_classes() click to toggle source

Which transaction errors to translate, blank by default.

    # File lib/sequel/database/transactions.rb
415 def database_error_classes
416   []
417 end
in_savepoint?(conn) click to toggle source

Whether the connection is currently inside a savepoint.

    # File lib/sequel/database/transactions.rb
420 def in_savepoint?(conn)
421   supports_savepoints? && savepoint_level(conn) > 1
422 end
remove_transaction(conn, committed) click to toggle source

Remove the current thread from the list of active transactions

    # File lib/sequel/database/transactions.rb
440 def remove_transaction(conn, committed)
441   callbacks = transaction_hooks(conn, committed)
442   if in_savepoint?(conn)
443     savepoint_callbacks = savepoint_hooks(conn, committed)
444     if committed
445       savepoint_rollback_callbacks = savepoint_hooks(conn, false)
446     end
447   end
448 
449   if transaction_finished?(conn)
450     h = _trans(conn)
451     rolled_back = !committed
452     Sequel.synchronize{h[:rolled_back] = rolled_back}
453     Sequel.synchronize{@transactions.delete(conn)}
454   elsif savepoint_callbacks || savepoint_rollback_callbacks
455     if committed
456       meth = in_savepoint?(conn) ? :add_savepoint_hook : :add_transaction_hook 
457 
458       if savepoint_callbacks
459         savepoint_callbacks.each do |block|
460           send(meth, conn, :after_commit, block)
461         end
462       end
463       
464       if savepoint_rollback_callbacks
465         savepoint_rollback_callbacks.each do |block|
466           send(meth, conn, :after_rollback, block)
467         end
468       end
469     else
470       savepoint_callbacks.each(&:call)
471     end
472   end
473 
474   callbacks.each(&:call) if callbacks
475 end
rollback_on_transaction_exit?(conn, opts) click to toggle source

Whether to rollback the transaction when exiting the transaction.

    # File lib/sequel/database/transactions.rb
483 def rollback_on_transaction_exit?(conn, opts)
484   return true if Thread.current.status == 'aborting'
485   h = _trans(conn)
486   if supports_savepoints?
487     h[:savepoints].last[:rollback_on_exit]
488   else
489     h[:rollback_on_exit]
490   end
491 end
rollback_savepoint_sql(depth) click to toggle source

SQL to rollback to a savepoint

    # File lib/sequel/database/transactions.rb
478 def rollback_savepoint_sql(depth)
479   "ROLLBACK TO SAVEPOINT autopoint_#{depth}"
480 end
rollback_transaction(conn, opts=OPTS) click to toggle source

Rollback the active transaction on the connection

    # File lib/sequel/database/transactions.rb
494 def rollback_transaction(conn, opts=OPTS)
495   if supports_savepoints?
496     depth = savepoint_level(conn)
497     log_connection_execute(conn, depth > 1 ? rollback_savepoint_sql(depth-1) : rollback_transaction_sql)
498   else
499     log_connection_execute(conn, rollback_transaction_sql)
500   end
501 end
rollback_transaction_sql() click to toggle source

SQL to ROLLBACK a transaction.

    # File lib/sequel/database/transactions.rb
504 def rollback_transaction_sql
505   'ROLLBACK'
506 end
savepoint_hooks(conn, committed) click to toggle source

Retrieve the savepoint hooks that should be run for the given connection and commit status. This expacts that you are already inside a savepoint when calling.

    # File lib/sequel/database/transactions.rb
427 def savepoint_hooks(conn, committed)
428   _trans(conn)[:savepoints].last[committed ? :after_commit : :after_rollback]
429 end
savepoint_level(conn) click to toggle source

Current savepoint level.

    # File lib/sequel/database/transactions.rb
521 def savepoint_level(conn)
522   _trans(conn)[:savepoints].length
523 end
set_transaction_isolation(conn, opts) click to toggle source

Set the transaction isolation level on the given connection

    # File lib/sequel/database/transactions.rb
509 def set_transaction_isolation(conn, opts)
510   if supports_transaction_isolation_levels? and level = opts.fetch(:isolation, transaction_isolation_level)
511     log_connection_execute(conn, set_transaction_isolation_sql(level))
512   end
513 end
set_transaction_isolation_sql(level) click to toggle source

SQL to set the transaction isolation level

    # File lib/sequel/database/transactions.rb
516 def set_transaction_isolation_sql(level)
517   "SET TRANSACTION ISOLATION LEVEL #{TRANSACTION_ISOLATION_LEVELS[level]}"
518 end
transaction_error(e, opts=OPTS) click to toggle source

Raise a database error unless the exception is an Rollback.

    # File lib/sequel/database/transactions.rb
526 def transaction_error(e, opts=OPTS)
527   if e.is_a?(Rollback)
528     raise e if opts[:rollback] == :reraise
529   else
530     raise_error(e, opts.merge(:classes=>database_error_classes))
531   end
532 end
transaction_finished?(conn) click to toggle source

Finish a subtransaction. If savepoints are supported, pops the current tansaction off the savepoint stack.

    # File lib/sequel/database/transactions.rb
536 def transaction_finished?(conn)
537   if supports_savepoints?
538     stack = _trans(conn)[:savepoints]
539     stack.pop
540     stack.empty?
541   else
542     true
543   end
544 end
transaction_hooks(conn, committed) click to toggle source

Retrieve the transaction hooks that should be run for the given connection and commit status.

    # File lib/sequel/database/transactions.rb
433 def transaction_hooks(conn, committed)
434   unless in_savepoint?(conn)
435     _trans(conn)[committed ? :after_commit : :after_rollback]
436   end
437 end
transaction_options(conn, opts) click to toggle source

Derive the transaction hash from the options passed to the transaction. Meant to be overridden.

    # File lib/sequel/database/transactions.rb
335 def transaction_options(conn, opts)
336   {}
337 end

9 - Methods that describe what the database supports

↑ top

Public Instance Methods

global_index_namespace?() click to toggle source

Whether the database uses a global namespace for the index, true by default. If false, the indexes are going to be namespaced per table.

   # File lib/sequel/database/features.rb
13 def global_index_namespace?
14   true
15 end
supports_create_table_if_not_exists?() click to toggle source

Whether the database supports CREATE TABLE IF NOT EXISTS syntax, false by default.

   # File lib/sequel/database/features.rb
19 def supports_create_table_if_not_exists?
20   false
21 end
supports_deferrable_constraints?() click to toggle source

Whether the database supports deferrable constraints, false by default as few databases do.

   # File lib/sequel/database/features.rb
25 def supports_deferrable_constraints?
26   false
27 end
supports_deferrable_foreign_key_constraints?() click to toggle source

Whether the database supports deferrable foreign key constraints, false by default as few databases do.

   # File lib/sequel/database/features.rb
31 def supports_deferrable_foreign_key_constraints?
32   supports_deferrable_constraints?
33 end
supports_drop_table_if_exists?() click to toggle source

Whether the database supports DROP TABLE IF EXISTS syntax, false by default.

   # File lib/sequel/database/features.rb
37 def supports_drop_table_if_exists?
38   supports_create_table_if_not_exists?
39 end
supports_foreign_key_parsing?() click to toggle source

Whether the database supports Database#foreign_key_list for parsing foreign keys.

   # File lib/sequel/database/features.rb
43 def supports_foreign_key_parsing?
44   respond_to?(:foreign_key_list)
45 end
supports_index_parsing?() click to toggle source

Whether the database supports Database#indexes for parsing indexes.

   # File lib/sequel/database/features.rb
48 def supports_index_parsing?
49   respond_to?(:indexes)
50 end
supports_partial_indexes?() click to toggle source

Whether the database supports partial indexes (indexes on a subset of a table), false by default.

   # File lib/sequel/database/features.rb
54 def supports_partial_indexes?
55   false
56 end
supports_prepared_transactions?() click to toggle source

Whether the database and adapter support prepared transactions (two-phase commit), false by default.

   # File lib/sequel/database/features.rb
60 def supports_prepared_transactions?
61   false
62 end
supports_savepoints?() click to toggle source

Whether the database and adapter support savepoints, false by default.

   # File lib/sequel/database/features.rb
65 def supports_savepoints?
66   false
67 end
supports_savepoints_in_prepared_transactions?() click to toggle source

Whether the database and adapter support savepoints inside prepared transactions (two-phase commit), false by default.

   # File lib/sequel/database/features.rb
71 def supports_savepoints_in_prepared_transactions?
72   supports_prepared_transactions? && supports_savepoints?
73 end
supports_schema_parsing?() click to toggle source

Whether the database supports schema parsing via Database#schema.

   # File lib/sequel/database/features.rb
76 def supports_schema_parsing?
77   respond_to?(:schema_parse_table, true)
78 end
supports_table_listing?() click to toggle source

Whether the database supports Database#tables for getting list of tables.

   # File lib/sequel/database/features.rb
81 def supports_table_listing?
82   respond_to?(:tables)
83 end
supports_transaction_isolation_levels?() click to toggle source

Whether the database and adapter support transaction isolation levels, false by default.

   # File lib/sequel/database/features.rb
91 def supports_transaction_isolation_levels?
92   false
93 end
supports_transactional_ddl?() click to toggle source

Whether DDL statements work correctly in transactions, false by default.

   # File lib/sequel/database/features.rb
96 def supports_transactional_ddl?
97   false
98 end
supports_view_listing?() click to toggle source

Whether the database supports Database#views for getting list of views.

   # File lib/sequel/database/features.rb
86 def supports_view_listing?
87   respond_to?(:views)
88 end
supports_views_with_check_option?() click to toggle source

Whether CREATE VIEW … WITH CHECK OPTION is supported, false by default.

    # File lib/sequel/database/features.rb
101 def supports_views_with_check_option?
102   !!view_with_check_option_support
103 end
supports_views_with_local_check_option?() click to toggle source

Whether CREATE VIEW … WITH LOCAL CHECK OPTION is supported, false by default.

    # File lib/sequel/database/features.rb
106 def supports_views_with_local_check_option?
107   view_with_check_option_support == :local
108 end

Private Instance Methods

can_add_primary_key_constraint_on_nullable_columns?() click to toggle source

Whether the database supports adding primary key constraints on NULLable columns, automatically making them NOT NULL. If false, the columns must be set NOT NULL before the primary key constraint is added.

    # File lib/sequel/database/features.rb
115 def can_add_primary_key_constraint_on_nullable_columns?
116   true
117 end
folds_unquoted_identifiers_to_uppercase?() click to toggle source

Whether this dataset considers unquoted identifiers as uppercase. True by default as that is the SQL standard

    # File lib/sequel/database/features.rb
121 def folds_unquoted_identifiers_to_uppercase?
122   true
123 end
supports_combining_alter_table_ops?() click to toggle source

Whether the database supports combining multiple alter table operations into a single query, false by default.

    # File lib/sequel/database/features.rb
127 def supports_combining_alter_table_ops?
128   false
129 end
supports_create_or_replace_view?() click to toggle source

Whether the database supports CREATE OR REPLACE VIEW. If not, support will be emulated by dropping the view first. false by default.

    # File lib/sequel/database/features.rb
133 def supports_create_or_replace_view?
134   false
135 end
supports_named_column_constraints?() click to toggle source

Whether the database supports named column constraints. True by default. Those that don't support named column constraints have to have column constraints converted to table constraints if the column constraints have names.

    # File lib/sequel/database/features.rb
141 def supports_named_column_constraints?
142   true
143 end
view_with_check_option_support() click to toggle source

Don't advertise support for WITH CHECK OPTION by default.

    # File lib/sequel/database/features.rb
146 def view_with_check_option_support
147   nil
148 end