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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 416

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.

:using

Specify which index method to use when creating this exclusion constraint (e.g. :btree, :gist etc).

:where

Specify an exclusion constraint on a subset of the table (internally PostgreSQL creates a partial index for this).



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 699

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 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 534

def add_foreign_key(from_table, to_table, **options)
  assert_valid_deferrable(options[:deferrable])

  super
end

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

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 485

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 894

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_constraint(table_name, column_name = nil, **options) ⇒ Object

Adds a new unique constraint to the table.

add_unique_constraint :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_constraint :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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 750

def add_unique_constraint(table_name, column_name = nil, **options)
  options = unique_constraint_options(table_name, column_name, options)
  at = create_alter_table(table_name)
  at.add_unique_constraint(column_name, options)

  execute schema_creation.accept(at)
end

#build_change_column_default_definition(table_name, column_name, default_or_changes) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 445

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 434

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 494

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 422

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



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 465

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 441

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 453

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



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 472

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 593

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 247

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

#client_min_messages=(level) ⇒ Object

Set the client message level.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 252

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

#collation ⇒ Object

Returns the current database collation.



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# 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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 825

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'



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# 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, force: nil, if_not_exists: nil) ⇒ Object

Creates a schema for the given schema name.



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

def create_schema(schema_name, force: nil, if_not_exists: nil)
  if force && if_not_exists
    raise ArgumentError, "Options `:force` and `:if_not_exists` cannot be used simultaneously."
  end

  if force
    drop_schema(schema_name, if_exists: true)
  end

  execute("CREATE SCHEMA#{' IF NOT EXISTS' if if_not_exists} #{quote_schema_name(schema_name)}")
end

#create_schema_dumper(options) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 841

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

#ctype ⇒ Object

Returns the current database ctype.



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# 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.



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# 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.



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# 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.



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

def default_sequence_name(table_name, pk = "id") # :nodoc:
  return nil if pk.is_a?(Array)

  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'



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# 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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 225

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:



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# 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.



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# 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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 707

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 619

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 889

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 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 540

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) 


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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 589

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 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 585

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

#index_name(table_name, options) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 529

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) 


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# 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.



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# 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 { |c| Utils.unquote_identifier(c.strip.gsub('""', '"')) } : []

    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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 315

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|gen_random_uuid'
    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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 368

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:



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

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.



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# 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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 722

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 499

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_constraint(table_name, column_name = nil, **options) ⇒ Object

Removes the given unique constraint from the table.

remove_unique_constraint :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_constraint.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 777

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

  at = create_alter_table(table_name)
  at.drop_unique_constraint(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.



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

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 522

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')



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 390

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
    # PostgreSQL automatically creates an index for PRIMARY KEY with name consisting of
    # truncated table name and "_pkey" suffix fitting into max_identifier_length number of characters.
    max_pkey_prefix = max_identifier_length - "_pkey".size
    idx = "#{table_name[0, max_pkey_prefix]}_pkey"
    new_idx = "#{new_name[0, max_pkey_prefix]}_pkey"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"

    # PostgreSQL automatically creates a sequence for PRIMARY KEY with name consisting of
    # truncated table name and "#{primary_key}_seq" suffix fitting into max_identifier_length number of characters.
    max_seq_prefix = max_identifier_length - "_#{pk}_seq".size
    if seq && seq.identifier == "#{table_name[0, max_seq_prefix]}_#{pk}_seq"
      new_seq = "#{new_name[0, max_seq_prefix]}_#{pk}_seq"
      execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
    end
  end
  rename_table_indexes(table_name, new_name, **options)
end

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

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



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 287

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:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 910

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

#schema_exists?(name) ⇒ Boolean

Returns true if schema exists.

Returns:

  • (Boolean) 


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# 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.



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# 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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 242

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.



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

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 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 267

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 272

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



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# 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:



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# 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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 787

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_constraint_options(table_name, column_name, options) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 758

def unique_constraint_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_constraint_name(table_name, column: column_name, **options)
  options
end

#unique_constraints(table_name) ⇒ Object

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



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 653

def unique_constraints(table_name)
  scope = quoted_scope(table_name)

  unique_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT c.conname, c.conrelid, c.conkey, 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|
    conkey = row["conkey"].delete("{}").split(",").map(&:to_i)
    columns = column_names_from_column_numbers(row["conrelid"], conkey)

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

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

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

#update_table_definition(table_name, base) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 837

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.



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

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



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 850

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.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 872

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