ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

add_exclusion_constraint(table_name, expression, **options)

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).

📝 Source code

# File activerecord/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

🔎 See on GitHub

add_foreign_key(from_table, to_table, **options)

📝 Source code

# File activerecord/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

🔎 See on GitHub

add_unique_constraint(table_name, column_name = nil, **options)

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.

📝 Source code

# File activerecord/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

🔎 See on GitHub

client_min_messages()

Returns the current client message level.

📝 Source code

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 247
        def client_min_messages
          query_value("SHOW client_min_messages", "SCHEMA")
        end

🔎 See on GitHub

client_min_messages=(level)

Set the client message level.

📝 Source code

# File activerecord/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

🔎 See on GitHub

collation()

Returns the current database collation.

📝 Source code

# File activerecord/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

🔎 See on GitHub

create_database(name, options = {})

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'

📝 Source code

# 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

🔎 See on GitHub

create_schema(schema_name, force: nil, if_not_exists: nil)

Creates a schema for the given schema name.

📝 Source code

# File activerecord/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

🔎 See on GitHub

ctype()

Returns the current database ctype.

📝 Source code

# File activerecord/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

🔎 See on GitHub

current_database()

Returns the current database name.

📝 Source code

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 176
        def current_database
          query_value("SELECT current_database()", "SCHEMA")
        end

🔎 See on GitHub

current_schema()

Returns the current schema name.

📝 Source code

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 181
        def current_schema
          query_value("SELECT current_schema", "SCHEMA")
        end

🔎 See on GitHub

drop_schema(schema_name, **options)

Drops the schema for the given schema name.

📝 Source code

# File activerecord/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

🔎 See on GitHub

encoding()

Returns the current database encoding format.

📝 Source code

# File activerecord/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

🔎 See on GitHub

exclusion_constraints(table_name)

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

📝 Source code

# File activerecord/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

🔎 See on GitHub

foreign_keys(table_name)

📝 Source code

# File activerecord/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

🔎 See on GitHub

foreign_table_exists?(table_name)

📝 Source code

# File activerecord/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

🔎 See on GitHub

foreign_tables()

📝 Source code

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 585
        def foreign_tables
          query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA")
        end

🔎 See on GitHub

index_name_exists?(table_name, index_name)

Verifies existence of an index with a given name.

📝 Source code

# 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

🔎 See on GitHub

remove_exclusion_constraint(table_name, expression = nil, **options)

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.

📝 Source code

# File activerecord/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

🔎 See on GitHub

remove_unique_constraint(table_name, column_name = nil, **options)

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.

📝 Source code

# File activerecord/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

🔎 See on GitHub

rename_index(table_name, old_name, new_name)

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

📝 Source code

# File activerecord/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

🔎 See on GitHub

rename_table(table_name, new_name, **options)

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')

📝 Source code

# File activerecord/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

🔎 See on GitHub

schema_exists?(name)

Returns true if schema exists.

📝 Source code

# 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

🔎 See on GitHub

schema_names()

Returns an array of schema names.

📝 Source code

# File activerecord/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

🔎 See on GitHub

schema_search_path()

Returns the active schema search path.

📝 Source code

# File activerecord/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

🔎 See on GitHub

schema_search_path=(schema_csv)

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.

📝 Source code

# File activerecord/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

🔎 See on GitHub

serial_sequence(table, column)

📝 Source code

# File activerecord/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

🔎 See on GitHub

unique_constraints(table_name)

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

📝 Source code

# File activerecord/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

🔎 See on GitHub

validate_check_constraint(table_name, **options)

Validates the given check constraint.

validate_check_constraint :products, name: "price_check"

The options hash accepts the same keys as add_check_constraint[rdoc-ref:ConnectionAdapters::SchemaStatements#add_check_constraint].

📝 Source code

# File activerecord/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

🔎 See on GitHub

validate_constraint(table_name, constraint_name)

Validates the given constraint.

Validates the constraint named constraint_name on accounts.

validate_constraint :accounts, :constraint_name

📝 Source code

# File activerecord/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

🔎 See on GitHub

validate_foreign_key(from_table, to_table = nil, **options)

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.

📝 Source code

# File activerecord/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

🔎 See on GitHub

ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

Methods

Instance Public methods

add_exclusion_constraint(table_name, expression, **options)

add_foreign_key(from_table, to_table, **options)

add_unique_constraint(table_name, column_name = nil, **options)

client_min_messages()

client_min_messages=(level)

collation()

create_database(name, options = {})

create_schema(schema_name, force: nil, if_not_exists: nil)

ctype()

current_database()

current_schema()

drop_schema(schema_name, **options)

encoding()

exclusion_constraints(table_name)

foreign_keys(table_name)

foreign_table_exists?(table_name)

foreign_tables()

index_name_exists?(table_name, index_name)

remove_exclusion_constraint(table_name, expression = nil, **options)

remove_unique_constraint(table_name, column_name = nil, **options)

rename_index(table_name, old_name, new_name)

rename_table(table_name, new_name, **options)

schema_exists?(name)

schema_names()

schema_search_path()

schema_search_path=(schema_csv)

serial_sequence(table, column)

unique_constraints(table_name)

validate_check_constraint(table_name, **options)

validate_constraint(table_name, constraint_name)

validate_foreign_key(from_table, to_table = nil, **options)