Module: ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

Included in:
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
Defined in:
lib/active_record/connection_adapters/postgresql/schema_statements.rb

Instance Method Summary collapse

Instance Method Details

#add_column(table_name, column_name, type, **options) ⇒ Object

:nodoc:



399
400
401
402
403
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 399

def add_column(table_name, column_name, type, **options) # :nodoc:
  clear_cache!
  super
  change_column_comment(table_name, column_name, options[:comment]) if options.key?(:comment)
end

#add_exclusion_constraint(table_name, expression, **options) ⇒ Object

Adds a new exclusion constraint to the table. expression is a String representation of a list of exclusion elements and operators.

add_exclusion_constraint :products, "price WITH =, availability_range WITH &&", using: :gist, name: "price_check"

generates:

ALTER TABLE "products" ADD CONSTRAINT price_check EXCLUDE USING gist (price WITH =, availability_range WITH &&)

The options hash can include the following keys:

:name

The constraint name. Defaults to excl_rails_<identifier>.

:deferrable

Specify whether or not the exclusion constraint should be deferrable. Valid values are false or :immediate or :deferred to specify the default behavior. Defaults to false.



690
691
692
693
694
695
696
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 690

def add_exclusion_constraint(table_name, expression, **options)
  options = exclusion_constraint_options(table_name, expression, options)
  at = create_alter_table(table_name)
  at.add_exclusion_constraint(expression, options)

  execute schema_creation.accept(at)
end

#add_foreign_key(from_table, to_table, **options) ⇒ Object 



517
518
519
520
521
522
523
524
525
526
527
528
529
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 517

def add_foreign_key(from_table, to_table, **options)
  if options[:deferrable] == true
    ActiveRecord.deprecator.warn(<<~MSG)
      `deferrable: true` is deprecated in favor of `deferrable: :immediate`, and will be removed in Rails 7.2.
    MSG

    options[:deferrable] = :immediate
  end

  assert_valid_deferrable(options[:deferrable])

  super
end

#add_index(table_name, column_name, **options) ⇒ Object

:nodoc:



468
469
470
471
472
473
474
475
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 468

def add_index(table_name, column_name, **options) # :nodoc:
  create_index = build_create_index_definition(table_name, column_name, **options)
  result = execute schema_creation.accept(create_index)

  index = create_index.index
  execute "COMMENT ON INDEX #{quote_column_name(index.name)} IS #{quote(index.comment)}" if index.comment
  result
end

#add_index_options(table_name, column_name, **options) ⇒ Object

:nodoc:



885
886
887
888
889
890
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 885

def add_index_options(table_name, column_name, **options) # :nodoc:
  if (where = options[:where]) && table_exists?(table_name) && column_exists?(table_name, where)
    options[:where] = quote_column_name(where)
  end
  super
end

#add_unique_key(table_name, column_name = nil, **options) ⇒ Object

Adds a new unique constraint to the table.

add_unique_key :sections, [:position], deferrable: :deferred, name: "unique_position"

generates:

ALTER TABLE "sections" ADD CONSTRAINT unique_position UNIQUE (position) DEFERRABLE INITIALLY DEFERRED

If you want to change an existing unique index to deferrable, you can use :using_index to create deferrable unique constraints.

add_unique_key :sections, deferrable: :deferred, name: "unique_position", using_index: "index_sections_on_position"

The options hash can include the following keys:

:name

The constraint name. Defaults to uniq_rails_<identifier>.

:deferrable

Specify whether or not the unique constraint should be deferrable. Valid values are false or :immediate or :deferred to specify the default behavior. Defaults to false.

:using_index

To specify an existing unique index name. Defaults to nil.



741
742
743
744
745
746
747
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 741

def add_unique_key(table_name, column_name = nil, **options)
  options = unique_key_options(table_name, column_name, options)
  at = create_alter_table(table_name)
  at.add_unique_key(column_name, options)

  execute schema_creation.accept(at)
end

#build_change_column_default_definition(table_name, column_name, default_or_changes) ⇒ Object

:nodoc:



428
429
430
431
432
433
434
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 428

def build_change_column_default_definition(table_name, column_name, default_or_changes) # :nodoc:
  column = column_for(table_name, column_name)
  return unless column

  default = extract_new_default_value(default_or_changes)
  ChangeColumnDefaultDefinition.new(column, default)
end

#build_change_column_definition(table_name, column_name, type, **options) ⇒ Object

Builds a ChangeColumnDefinition object.

This definition object contains information about the column change that would occur if the same arguments were passed to #change_column. See #change_column for information about passing a table_name, column_name, type and other options that can be passed.



417
418
419
420
421
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 417

def build_change_column_definition(table_name, column_name, type, **options) # :nodoc:
  td = create_table_definition(table_name)
  cd = td.new_column_definition(column_name, type, **options)
  ChangeColumnDefinition.new(cd, column_name)
end

#build_create_index_definition(table_name, column_name, **options) ⇒ Object

:nodoc:



477
478
479
480
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 477

def build_create_index_definition(table_name, column_name, **options) # :nodoc:
  index, algorithm, if_not_exists = add_index_options(table_name, column_name, **options)
  CreateIndexDefinition.new(index, algorithm, if_not_exists)
end

#change_column(table_name, column_name, type, **options) ⇒ Object

:nodoc:



405
406
407
408
409
410
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 405

def change_column(table_name, column_name, type, **options) # :nodoc:
  clear_cache!
  sqls, procs = Array(change_column_for_alter(table_name, column_name, type, **options)).partition { |v| v.is_a?(String) }
  execute "ALTER TABLE #{quote_table_name(table_name)} #{sqls.join(", ")}"
  procs.each(&:call)
end

#change_column_comment(table_name, column_name, comment_or_changes) ⇒ Object

Adds comment for given table column or drops it if comment is a nil



448
449
450
451
452
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 448

def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:
  clear_cache!
  comment = extract_new_comment_value(comment_or_changes)
  execute "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS #{quote(comment)}"
end

#change_column_default(table_name, column_name, default_or_changes) ⇒ Object

Changes the default value of a table column.



424
425
426
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 424

def change_column_default(table_name, column_name, default_or_changes) # :nodoc:
  execute "ALTER TABLE #{quote_table_name(table_name)} #{change_column_default_for_alter(table_name, column_name, default_or_changes)}"
end

#change_column_null(table_name, column_name, null, default = nil) ⇒ Object

:nodoc:



436
437
438
439
440
441
442
443
444
445
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 436

def change_column_null(table_name, column_name, null, default = nil) # :nodoc:
  validate_change_column_null_argument!(null)

  clear_cache!
  unless null || default.nil?
    column = column_for(table_name, column_name)
    execute "UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote_default_expression(default, column)} WHERE #{quote_column_name(column_name)} IS NULL" if column
  end
  execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL"
end

#change_table_comment(table_name, comment_or_changes) ⇒ Object

Adds comment for given table or drops it if comment is a nil



455
456
457
458
459
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 455

def change_table_comment(table_name, comment_or_changes) # :nodoc:
  clear_cache!
  comment = extract_new_comment_value(comment_or_changes)
  execute "COMMENT ON TABLE #{quote_table_name(table_name)} IS #{quote(comment)}"
end

#check_constraints(table_name) ⇒ Object

:nodoc:



584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 584

def check_constraints(table_name) # :nodoc:
  scope = quoted_scope(table_name)

  check_info = internal_exec_query(<<-SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT conname, pg_get_constraintdef(c.oid, true) AS constraintdef, c.convalidated AS valid
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'c'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  check_info.map do |row|
    options = {
      name: row["conname"],
      validate: row["valid"]
    }
    expression = row["constraintdef"][/CHECK \((.+)\)/m, 1]

    CheckConstraintDefinition.new(table_name, expression, options)
  end
end

#client_min_messages ⇒ Object

Returns the current client message level.



239
240
241
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 239

def client_min_messages
  query_value("SHOW client_min_messages", "SCHEMA")
end

#client_min_messages=(level) ⇒ Object

Set the client message level.



244
245
246
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 244

def client_min_messages=(level)
  internal_execute("SET client_min_messages TO '#{level}'")
end

#collation ⇒ Object

Returns the current database collation.



191
192
193
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 191

def collation
  query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

#columns_for_distinct(columns, orders) ⇒ Object

PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.



816
817
818
819
820
821
822
823
824
825
826
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 816

def columns_for_distinct(columns, orders) # :nodoc:
  order_columns = orders.compact_blank.map { |s|
    # Convert Arel node to string
    s = visitor.compile(s) unless s.is_a?(String)
    # Remove any ASC/DESC modifiers
    s.gsub(/\s+(?:ASC|DESC)\b/i, "")
     .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, "")
  }.compact_blank.map.with_index { |column, i| "#{column} AS alias_#{i}" }

  (order_columns << super).join(", ")
end

#create_database(name, options = {}) ⇒ Object

Create a new PostgreSQL database. Options include :owner, :template, :encoding (defaults to utf8), :collation, :ctype, :tablespace, and :connection_limit (note that MySQL uses :charset while PostgreSQL uses :encoding).

Example:

create_database config[:database], config
create_database 'foo_development', encoding: 'unicode'



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 22

def create_database(name, options = {})
  options = { encoding: "utf8" }.merge!(options.symbolize_keys)

  option_string = options.each_with_object(+"") do |(key, value), memo|
    memo << case key
            when :owner
              " OWNER = \"#{value}\""
            when :template
              " TEMPLATE = \"#{value}\""
            when :encoding
              " ENCODING = '#{value}'"
            when :collation
              " LC_COLLATE = '#{value}'"
            when :ctype
              " LC_CTYPE = '#{value}'"
            when :tablespace
              " TABLESPACE = \"#{value}\""
            when :connection_limit
              " CONNECTION LIMIT = #{value}"
            else
              ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end

#create_schema(schema_name) ⇒ Object

Creates a schema for the given schema name.



212
213
214
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 212

def create_schema(schema_name)
  execute "CREATE SCHEMA #{quote_schema_name(schema_name)}"
end

#create_schema_dumper(options) ⇒ Object

:nodoc:



832
833
834
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 832

def create_schema_dumper(options) # :nodoc:
  PostgreSQL::SchemaDumper.create(self, options)
end

#ctype ⇒ Object

Returns the current database ctype.



196
197
198
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 196

def ctype
  query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

#current_database ⇒ Object

Returns the current database name.



176
177
178
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 176

def current_database
  query_value("SELECT current_database()", "SCHEMA")
end

#current_schema ⇒ Object

Returns the current schema name.



181
182
183
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 181

def current_schema
  query_value("SELECT current_schema", "SCHEMA")
end

#default_sequence_name(table_name, pk = "id") ⇒ Object

Returns the sequence name for a table’s primary key or some other specified key.



249
250
251
252
253
254
255
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 249

def default_sequence_name(table_name, pk = "id") # :nodoc:
  result = serial_sequence(table_name, pk)
  return nil unless result
  Utils.extract_schema_qualified_name(result).to_s
rescue ActiveRecord::StatementInvalid
  PostgreSQL::Name.new(nil, "#{table_name}_#{pk}_seq").to_s
end

#drop_database(name) ⇒ Object

Drops a PostgreSQL database.

Example:

drop_database 'matt_development'



53
54
55
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 53

def drop_database(name) # :nodoc:
  execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
end

#drop_schema(schema_name, **options) ⇒ Object

Drops the schema for the given schema name.



217
218
219
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 217

def drop_schema(schema_name, **options)
  execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE"
end

#drop_table(table_name, **options) ⇒ Object

:nodoc:



57
58
59
60
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 57

def drop_table(table_name, **options) # :nodoc:
  schema_cache.clear_data_source_cache!(table_name.to_s)
  execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

#encoding ⇒ Object

Returns the current database encoding format.



186
187
188
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 186

def encoding
  query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

#exclusion_constraint_options(table_name, expression, options) ⇒ Object

:nodoc:



698
699
700
701
702
703
704
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 698

def exclusion_constraint_options(table_name, expression, options) # :nodoc:
  assert_valid_deferrable(options[:deferrable])

  options = options.dup
  options[:name] ||= exclusion_constraint_name(table_name, expression: expression, **options)
  options
end

#exclusion_constraints(table_name) ⇒ Object

Returns an array of exclusion constraints for the given table. The exclusion constraints are represented as ExclusionConstraintDefinition objects.



610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 610

def exclusion_constraints(table_name)
  scope = quoted_scope(table_name)

  exclusion_info = internal_exec_query(<<-SQL, "SCHEMA")
    SELECT conname, pg_get_constraintdef(c.oid) AS constraintdef, c.condeferrable, c.condeferred
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'x'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  exclusion_info.map do |row|
    method_and_elements, predicate = row["constraintdef"].split(" WHERE ")
    method_and_elements_parts = method_and_elements.match(/EXCLUDE(?: USING (?<using>\S+))? \((?<expression>.+)\)/)
    predicate.remove!(/ DEFERRABLE(?: INITIALLY (?:IMMEDIATE|DEFERRED))?/) if predicate
    predicate = predicate.from(2).to(-3) if predicate # strip 2 opening and closing parentheses

    deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

    options = {
      name: row["conname"],
      using: method_and_elements_parts["using"].to_sym,
      where: predicate,
      deferrable: deferrable
    }

    ExclusionConstraintDefinition.new(table_name, method_and_elements_parts["expression"], options)
  end
end

#foreign_key_column_for(table_name, column_name) ⇒ Object

:nodoc:



880
881
882
883
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 880

def foreign_key_column_for(table_name, column_name) # :nodoc:
  _schema, table_name = extract_schema_qualified_name(table_name)
  super
end

#foreign_keys(table_name) ⇒ Object 



531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 531

def foreign_keys(table_name)
  scope = quoted_scope(table_name)
  fk_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete, c.convalidated AS valid, c.condeferrable AS deferrable, c.condeferred AS deferred, c.conkey, c.confkey, c.conrelid, c.confrelid
    FROM pg_constraint c
    JOIN pg_class t1 ON c.conrelid = t1.oid
    JOIN pg_class t2 ON c.confrelid = t2.oid
    JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
    JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
    JOIN pg_namespace t3 ON c.connamespace = t3.oid
    WHERE c.contype = 'f'
      AND t1.relname = #{scope[:name]}
      AND t3.nspname = #{scope[:schema]}
    ORDER BY c.conname
  SQL

  fk_info.map do |row|
    to_table = Utils.unquote_identifier(row["to_table"])
    conkey = row["conkey"].scan(/\d+/).map(&:to_i)
    confkey = row["confkey"].scan(/\d+/).map(&:to_i)

    if conkey.size > 1
      column = column_names_from_column_numbers(row["conrelid"], conkey)
      primary_key = column_names_from_column_numbers(row["confrelid"], confkey)
    else
      column = Utils.unquote_identifier(row["column"])
      primary_key = row["primary_key"]
    end

    options = {
      column: column,
      name: row["name"],
      primary_key: primary_key
    }

    options[:on_delete] = extract_foreign_key_action(row["on_delete"])
    options[:on_update] = extract_foreign_key_action(row["on_update"])
    options[:deferrable] = extract_constraint_deferrable(row["deferrable"], row["deferred"])

    options[:validate] = row["valid"]

    ForeignKeyDefinition.new(table_name, to_table, options)
  end
end

#foreign_table_exists?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


580
581
582
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 580

def foreign_table_exists?(table_name)
  query_values(data_source_sql(table_name, type: "FOREIGN TABLE"), "SCHEMA").any? if table_name.present?
end

#foreign_tables ⇒ Object 



576
577
578
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 576

def foreign_tables
  query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA")
end

#index_name(table_name, options) ⇒ Object

:nodoc:



512
513
514
515
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 512

def index_name(table_name, options) # :nodoc:
  _schema, table_name = extract_schema_qualified_name(table_name.to_s)
  super
end

#index_name_exists?(table_name, index_name) ⇒ Boolean

Verifies existence of an index with a given name.

Returns:

  • (Boolean) 


68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 68

def index_name_exists?(table_name, index_name)
  table = quoted_scope(table_name)
  index = quoted_scope(index_name)

  query_value(<<~SQL, "SCHEMA").to_i > 0
    SELECT COUNT(*)
    FROM pg_class t
    INNER JOIN pg_index d ON t.oid = d.indrelid
    INNER JOIN pg_class i ON d.indexrelid = i.oid
    LEFT JOIN pg_namespace n ON n.oid = t.relnamespace
    WHERE i.relkind IN ('i', 'I')
      AND i.relname = #{index[:name]}
      AND t.relname = #{table[:name]}
      AND n.nspname = #{table[:schema]}
  SQL
end

#indexes(table_name) ⇒ Object

Returns an array of indexes for the given table.



86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 86

def indexes(table_name) # :nodoc:
  scope = quoted_scope(table_name)

  result = query(<<~SQL, "SCHEMA")
    SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
                    pg_catalog.obj_description(i.oid, 'pg_class') AS comment, d.indisvalid
    FROM pg_class t
    INNER JOIN pg_index d ON t.oid = d.indrelid
    INNER JOIN pg_class i ON d.indexrelid = i.oid
    LEFT JOIN pg_namespace n ON n.oid = t.relnamespace
    WHERE i.relkind IN ('i', 'I')
      AND d.indisprimary = 'f'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
    ORDER BY i.relname
  SQL

  result.map do |row|
    index_name = row[0]
    unique = row[1]
    indkey = row[2].split(" ").map(&:to_i)
    inddef = row[3]
    oid = row[4]
    comment = row[5]
    valid = row[6]
    using, expressions, include, nulls_not_distinct, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: INCLUDE \((.+?)\))?( NULLS NOT DISTINCT)?(?: WHERE (.+))?\z/m).flatten

    orders = {}
    opclasses = {}
    include_columns = include ? include.split(",").map(&:strip) : []

    if indkey.include?(0)
      columns = expressions
    else
      columns = column_names_from_column_numbers(oid, indkey)

      # prevent INCLUDE columns from being matched
      columns.reject! { |c| include_columns.include?(c) }

      # add info on sort order (only desc order is explicitly specified, asc is the default)
      # and non-default opclasses
      expressions.scan(/(?<column>\w+)"?\s?(?<opclass>\w+_ops(_\w+)?)?\s?(?<desc>DESC)?\s?(?<nulls>NULLS (?:FIRST|LAST))?/).each do |column, opclass, desc, nulls|
        opclasses[column] = opclass.to_sym if opclass
        if nulls
          orders[column] = [desc, nulls].compact.join(" ")
        else
          orders[column] = :desc if desc
        end
      end
    end

    IndexDefinition.new(
      table_name,
      index_name,
      unique,
      columns,
      orders: orders,
      opclasses: opclasses,
      where: where,
      using: using.to_sym,
      include: include_columns.presence,
      nulls_not_distinct: nulls_not_distinct.present?,
      comment: comment.presence,
      valid: valid
    )
  end
end

#pk_and_sequence_for(table) ⇒ Object

Returns a table’s primary key and belonging sequence.



305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 305

def pk_and_sequence_for(table) # :nodoc:
  # First try looking for a sequence with a dependency on the
  # given table's primary key.
  result = query(<<~SQL, "SCHEMA")[0]
    SELECT attr.attname, nsp.nspname, seq.relname
    FROM pg_class      seq,
         pg_attribute  attr,
         pg_depend     dep,
         pg_constraint cons,
         pg_namespace  nsp
    WHERE seq.oid           = dep.objid
      AND seq.relkind       = 'S'
      AND attr.attrelid     = dep.refobjid
      AND attr.attnum       = dep.refobjsubid
      AND attr.attrelid     = cons.conrelid
      AND attr.attnum       = cons.conkey[1]
      AND seq.relnamespace  = nsp.oid
      AND cons.contype      = 'p'
      AND dep.classid       = 'pg_class'::regclass
      AND dep.refobjid      = #{quote(quote_table_name(table))}::regclass
  SQL

  if result.nil? || result.empty?
    result = query(<<~SQL, "SCHEMA")[0]
      SELECT attr.attname, nsp.nspname,
        CASE
          WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
          WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
            substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
                   strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
          ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)
        END
      FROM pg_class       t
      JOIN pg_attribute   attr ON (t.oid = attrelid)
      JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)
      JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
      JOIN pg_namespace   nsp  ON (t.relnamespace = nsp.oid)
      WHERE t.oid = #{quote(quote_table_name(table))}::regclass
        AND cons.contype = 'p'
        AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate'
    SQL
  end

  pk = result.shift
  if result.last
    [pk, PostgreSQL::Name.new(*result)]
  else
    [pk, nil]
  end
rescue
  nil
end

#primary_keys(table_name) ⇒ Object

:nodoc:



358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 358

def primary_keys(table_name) # :nodoc:
  query_values(<<~SQL, "SCHEMA")
    SELECT a.attname
      FROM (
             SELECT indrelid, indkey, generate_subscripts(indkey, 1) idx
               FROM pg_index
              WHERE indrelid = #{quote(quote_table_name(table_name))}::regclass
                AND indisprimary
           ) i
      JOIN pg_attribute a
        ON a.attrelid = i.indrelid
       AND a.attnum = i.indkey[i.idx]
     ORDER BY i.idx
  SQL
end

#quoted_include_columns_for_index(column_names) ⇒ Object

:nodoc:



892
893
894
895
896
897
898
899
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 892

def quoted_include_columns_for_index(column_names) # :nodoc:
  return quote_column_name(column_names) if column_names.is_a?(Symbol)

  quoted_columns = column_names.each_with_object({}) do |name, result|
    result[name.to_sym] = quote_column_name(name).dup
  end
  add_options_for_index_columns(quoted_columns).values.join(", ")
end

#recreate_database(name, options = {}) ⇒ Object

Drops the database specified on the name attribute and creates it again using the provided options.



9
10
11
12
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 9

def recreate_database(name, options = {}) # :nodoc:
  drop_database(name)
  create_database(name, options)
end

#remove_exclusion_constraint(table_name, expression = nil, **options) ⇒ Object

Removes the given exclusion constraint from the table.

remove_exclusion_constraint :products, name: "price_check"

The expression parameter will be ignored if present. It can be helpful to provide this in a migration’s change method so it can be reverted. In that case, expression will be used by #add_exclusion_constraint.



713
714
715
716
717
718
719
720
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 713

def remove_exclusion_constraint(table_name, expression = nil, **options)
  excl_name_to_delete = exclusion_constraint_for!(table_name, expression: expression, **options).name

  at = create_alter_table(table_name)
  at.drop_exclusion_constraint(excl_name_to_delete)

  execute schema_creation.accept(at)
end

#remove_index(table_name, column_name = nil, **options) ⇒ Object

:nodoc:



482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 482

def remove_index(table_name, column_name = nil, **options) # :nodoc:
  table = Utils.extract_schema_qualified_name(table_name.to_s)

  if options.key?(:name)
    provided_index = Utils.extract_schema_qualified_name(options[:name].to_s)

    options[:name] = provided_index.identifier
    table = PostgreSQL::Name.new(provided_index.schema, table.identifier) unless table.schema.present?

    if provided_index.schema.present? && table.schema != provided_index.schema
      raise ArgumentError.new("Index schema '#{provided_index.schema}' does not match table schema '#{table.schema}'")
    end
  end

  return if options[:if_exists] && !index_exists?(table_name, column_name, **options)

  index_to_remove = PostgreSQL::Name.new(table.schema, index_name_for_remove(table.to_s, column_name, options))

  execute "DROP INDEX #{index_algorithm(options[:algorithm])} #{quote_table_name(index_to_remove)}"
end

#remove_unique_key(table_name, column_name = nil, **options) ⇒ Object

Removes the given unique constraint from the table.

remove_unique_key :sections, name: "unique_position"

The column_name parameter will be ignored if present. It can be helpful to provide this in a migration’s change method so it can be reverted. In that case, column_name will be used by #add_unique_key.



768
769
770
771
772
773
774
775
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 768

def remove_unique_key(table_name, column_name = nil, **options)
  unique_name_to_delete = unique_key_for!(table_name, column: column_name, **options).name

  at = create_alter_table(table_name)
  at.drop_unique_key(unique_name_to_delete)

  execute schema_creation.accept(at)
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

Renames a column in a table.



462
463
464
465
466
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 462

def rename_column(table_name, column_name, new_column_name) # :nodoc:
  clear_cache!
  execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
  rename_column_indexes(table_name, column_name, new_column_name)
end

#rename_index(table_name, old_name, new_name) ⇒ Object

Renames an index of a table. Raises error if length of new index name is greater than allowed limit.



505
506
507
508
509
510
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 505

def rename_index(table_name, old_name, new_name)
  validate_index_length!(table_name, new_name)

  schema, = extract_schema_qualified_name(table_name)
  execute "ALTER INDEX #{quote_table_name(schema) + '.' if schema}#{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end

#rename_table(table_name, new_name, **options) ⇒ Object

Renames a table. Also renames a table’s primary key sequence if the sequence name exists and matches the Active Record default.

Example:

rename_table('octopuses', 'octopi')



380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 380

def rename_table(table_name, new_name, **options)
  validate_table_length!(new_name) unless options[:_uses_legacy_table_name]
  clear_cache!
  schema_cache.clear_data_source_cache!(table_name.to_s)
  schema_cache.clear_data_source_cache!(new_name.to_s)
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if pk
    idx = "#{table_name}_pkey"
    new_idx = "#{new_name}_pkey"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"
    if seq && seq.identifier == "#{table_name}_#{pk}_seq"
      new_seq = "#{new_name}_#{pk}_seq"
      execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
    end
  end
  rename_table_indexes(table_name, new_name)
end

#reset_pk_sequence!(table, pk = nil, sequence = nil) ⇒ Object

Resets the sequence of a table’s primary key to the maximum value.



277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 277

def reset_pk_sequence!(table, pk = nil, sequence = nil) # :nodoc:
  unless pk && sequence
    default_pk, default_sequence = pk_and_sequence_for(table)

    pk ||= default_pk
    sequence ||= default_sequence
  end

  if @logger && pk && !sequence
    @logger.warn "#{table} has primary key #{pk} with no default sequence."
  end

  if pk && sequence
    quoted_sequence = quote_table_name(sequence)
    max_pk = query_value("SELECT MAX(#{quote_column_name pk}) FROM #{quote_table_name(table)}", "SCHEMA")
    if max_pk.nil?
      if database_version >= 10_00_00
        minvalue = query_value("SELECT seqmin FROM pg_sequence WHERE seqrelid = #{quote(quoted_sequence)}::regclass", "SCHEMA")
      else
        minvalue = query_value("SELECT min_value FROM #{quoted_sequence}", "SCHEMA")
      end
    end

    query_value("SELECT setval(#{quote(quoted_sequence)}, #{max_pk || minvalue}, #{max_pk ? true : false})", "SCHEMA")
  end
end

#schema_creation ⇒ Object

:nodoc:



901
902
903
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 901

def schema_creation  # :nodoc:
  PostgreSQL::SchemaCreation.new(self)
end

#schema_exists?(name) ⇒ Boolean

Returns true if schema exists.

Returns:

  • (Boolean) 


63
64
65
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 63

def schema_exists?(name)
  query_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
end

#schema_names ⇒ Object

Returns an array of schema names.



201
202
203
204
205
206
207
208
209
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 201

def schema_names
  query_values(<<~SQL, "SCHEMA")
    SELECT nspname
      FROM pg_namespace
     WHERE nspname !~ '^pg_.*'
       AND nspname NOT IN ('information_schema')
     ORDER by nspname;
  SQL
end

#schema_search_path ⇒ Object

Returns the active schema search path.



234
235
236
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 234

def schema_search_path
  @schema_search_path ||= query_value("SHOW search_path", "SCHEMA")
end

#schema_search_path=(schema_csv) ⇒ Object

Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => ‘$user’). See: www.postgresql.org/docs/current/static/ddl-schemas.html

This should be not be called manually but set in database.yml.



226
227
228
229
230
231
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 226

def schema_search_path=(schema_csv)
  if schema_csv
    internal_execute("SET search_path TO #{schema_csv}")
    @schema_search_path = schema_csv
  end
end

#serial_sequence(table, column) ⇒ Object 



257
258
259
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 257

def serial_sequence(table, column)
  query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA")
end

#set_pk_sequence!(table, value) ⇒ Object

Sets the sequence of a table’s primary key to the specified value.



262
263
264
265
266
267
268
269
270
271
272
273
274
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 262

def set_pk_sequence!(table, value) # :nodoc:
  pk, sequence = pk_and_sequence_for(table)

  if pk
    if sequence
      quoted_sequence = quote_table_name(sequence)

      query_value("SELECT setval(#{quote(quoted_sequence)}, #{value})", "SCHEMA")
    else
      @logger.warn "#{table} has primary key #{pk} with no default sequence." if @logger
    end
  end
end

#table_comment(table_name) ⇒ Object

Returns a comment stored in database for given table



161
162
163
164
165
166
167
168
169
170
171
172
173
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 161

def table_comment(table_name) # :nodoc:
  scope = quoted_scope(table_name, type: "BASE TABLE")
  if scope[:name]
    query_value(<<~SQL, "SCHEMA")
      SELECT pg_catalog.obj_description(c.oid, 'pg_class')
      FROM pg_catalog.pg_class c
        LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
      WHERE c.relname = #{scope[:name]}
        AND c.relkind IN (#{scope[:type]})
        AND n.nspname = #{scope[:schema]}
    SQL
  end
end

#table_options(table_name) ⇒ Object

:nodoc:



154
155
156
157
158
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 154

def table_options(table_name) # :nodoc:
  if comment = table_comment(table_name)
    { comment: comment }
  end
end

#type_to_sql(type, limit: nil, precision: nil, scale: nil, array: nil, enum_type: nil) ⇒ Object

Maps logical Rails types to PostgreSQL-specific data types.



778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 778

def type_to_sql(type, limit: nil, precision: nil, scale: nil, array: nil, enum_type: nil, **) # :nodoc:
  sql = \
    case type.to_s
    when "binary"
      # PostgreSQL doesn't support limits on binary (bytea) columns.
      # The hard limit is 1GB, because of a 32-bit size field, and TOAST.
      case limit
      when nil, 0..0x3fffffff; super(type)
      else raise ArgumentError, "No binary type has byte size #{limit}. The limit on binary can be at most 1GB - 1byte."
      end
    when "text"
      # PostgreSQL doesn't support limits on text columns.
      # The hard limit is 1GB, according to section 8.3 in the manual.
      case limit
      when nil, 0..0x3fffffff; super(type)
      else raise ArgumentError, "No text type has byte size #{limit}. The limit on text can be at most 1GB - 1byte."
      end
    when "integer"
      case limit
      when 1, 2; "smallint"
      when nil, 3, 4; "integer"
      when 5..8; "bigint"
      else raise ArgumentError, "No integer type has byte size #{limit}. Use a numeric with scale 0 instead."
      end
    when "enum"
      raise ArgumentError, "enum_type is required for enums" if enum_type.nil?

      enum_type
    else
      super
    end

  sql = "#{sql}[]" if array && type != :primary_key
  sql
end

#unique_key_options(table_name, column_name, options) ⇒ Object

:nodoc:



749
750
751
752
753
754
755
756
757
758
759
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 749

def unique_key_options(table_name, column_name, options) # :nodoc:
  assert_valid_deferrable(options[:deferrable])

  if column_name && options[:using_index]
    raise ArgumentError, "Cannot specify both column_name and :using_index options."
  end

  options = options.dup
  options[:name] ||= unique_key_name(table_name, column: column_name, **options)
  options
end

#unique_keys(table_name) ⇒ Object

Returns an array of unique constraints for the given table. The unique constraints are represented as UniqueKeyDefinition objects.



644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 644

def unique_keys(table_name)
  scope = quoted_scope(table_name)

  unique_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT c.conname, c.conindid, c.condeferrable, c.condeferred
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'u'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  unique_info.map do |row|
    deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

    columns = query_values(<<~SQL, "SCHEMA")
      SELECT a.attname
      FROM pg_attribute a
      WHERE a.attrelid = #{row['conindid']}
      ORDER BY a.attnum
    SQL

    options = {
      name: row["conname"],
      deferrable: deferrable
    }

    UniqueKeyDefinition.new(table_name, columns, options)
  end
end

#update_table_definition(table_name, base) ⇒ Object

:nodoc:



828
829
830
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 828

def update_table_definition(table_name, base) # :nodoc:
  PostgreSQL::Table.new(table_name, base)
end

#validate_check_constraint(table_name, **options) ⇒ Object

Validates the given check constraint.

validate_check_constraint :products, name: "price_check"

The options hash accepts the same keys as add_check_constraint.



874
875
876
877
878
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 874

def validate_check_constraint(table_name, **options)
  chk_name_to_validate = check_constraint_for!(table_name, **options).name

  validate_constraint table_name, chk_name_to_validate
end

#validate_constraint(table_name, constraint_name) ⇒ Object

Validates the given constraint.

Validates the constraint named constraint_name on accounts.

validate_constraint :accounts, :constraint_name



841
842
843
844
845
846
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 841

def validate_constraint(table_name, constraint_name)
  at = create_alter_table table_name
  at.validate_constraint constraint_name

  execute schema_creation.accept(at)
end

#validate_foreign_key(from_table, to_table = nil, **options) ⇒ Object

Validates the given foreign key.

Validates the foreign key on accounts.branch_id.

validate_foreign_key :accounts, :branches

Validates the foreign key on accounts.owner_id.

validate_foreign_key :accounts, column: :owner_id

Validates the foreign key named special_fk_name on the accounts table.

validate_foreign_key :accounts, name: :special_fk_name

The options hash accepts the same keys as SchemaStatements#add_foreign_key.



863
864
865
866
867
 
# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 863

def validate_foreign_key(from_table, to_table = nil, **options)
  fk_name_to_validate = foreign_key_for!(from_table, to_table: to_table, **options).name

  validate_constraint from_table, fk_name_to_validate
end