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

Defined in:
activerecord/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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 403

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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 669

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_index(table_name, column_name, **options) ⇒ Object

:nodoc:



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

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_unique_key(table_name, column_name, **options) ⇒ Object

Adds a new unique constraint to the table.

PostgreSQL allows users to create a unique constraints on top of the unique index that cannot be deferred. In this case, even if users creates deferrable unique constraint, the existing unique index does not allow users to violate uniqueness within the transaction. If you want to change existing unique index to deferrable, you need execute ‘remove_index` before creating deferrable unique constraints.

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

generates:

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

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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 720

def add_unique_key(table_name, column_name, **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:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 432

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 421

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 481

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 409

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 452

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 428

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 440

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 459

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 563

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

  check_info = exec_query(<<-SQL, "SCHEMA", allow_retry: true, uses_transaction: 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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 243

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 248

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 195

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 791

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 'activerecord/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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 216

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

#create_schema_dumper(options) ⇒ Object

:nodoc:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 807

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

#ctype ⇒ Object

Returns the current database ctype.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 200

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 180

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

#current_schema ⇒ Object

Returns the current schema name.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 185

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 253

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'



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# File 'activerecord/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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 221

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 'activerecord/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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 190

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 677

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

def exclusion_constraints(table_name)
  scope = quoted_scope(table_name)

  exclusion_info = 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) ⇒ Object

:nodoc:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 855

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

#foreign_keys(table_name) ⇒ Object 



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 521

def foreign_keys(table_name)
  scope = quoted_scope(table_name)
  fk_info = exec_query(<<~SQL, "SCHEMA", allow_retry: true, uses_transaction: 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
    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|
    options = {
      column: Utils.unquote_identifier(row["column"]),
      name: row["name"],
      primary_key: row["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_foreign_key_deferrable(row["deferrable"], row["deferred"])

    options[:validate] = row["valid"]
    to_table = Utils.unquote_identifier(row["to_table"])

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

#foreign_table_exists?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 559

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 555

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 516

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 'activerecord/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 'activerecord/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, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: NULLS(?: NOT)? DISTINCT)?(?: INCLUDE \((.+?)\))?(?: WHERE (.+))?\z/m).flatten

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

    if indkey.include?(0)
      columns = expressions
    else
      columns = Hash[query(<<~SQL, "SCHEMA")].values_at(*indkey).compact
        SELECT a.attnum, a.attname
        FROM pg_attribute a
        WHERE a.attrelid = #{oid}
        AND a.attnum IN (#{indkey.join(",")})
      SQL

      # 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.map(&:to_sym).presence,
      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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 309

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:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 362

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 860

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 'activerecord/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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 692

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 486

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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 743

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



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 466

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 509

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 384

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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 281

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 869

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 'activerecord/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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 205

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 238

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 230

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 261

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 266

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 165

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 158

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 753

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:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 728

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

  options = options.dup
  options[:name] ||= unique_key_name(table_name, column_name: 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.



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 623

def unique_keys(table_name)
  scope = quoted_scope(table_name)

  unique_info = exec_query(<<~SQL, "SCHEMA", allow_retry: true, uses_transaction: 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:



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# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 803

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 849

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 816

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 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 838

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