Skip to Content Skip to Search
Methods
A
C
D
E
F
I
R
S
U
V

Instance Public methods

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 745 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)

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 578 def add_foreign_key(from_table, to_table, **options) assert_valid_deferrable(options[:deferrable]) super end

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", nulls_not_distinct: true

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.

:nulls_not_distinct

Create a unique constraint where NULLs are treated equally. Note: only supported by PostgreSQL version 15.0.0 and greater.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 796 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

client_min_messages()

Returns the current client message level.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 291 def client_min_messages query_value("SHOW client_min_messages", "SCHEMA") end

client_min_messages=(level)

Set the client message level.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 296 def client_min_messages=(level) internal_execute("SET client_min_messages TO '#{level}'", "SCHEMA") end

collation()

Returns the current database collation.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 235 def collation query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA") end

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: show | on GitHub 

# 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, force: nil, if_not_exists: nil)

Creates a schema for the given schema name.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 256 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

ctype()

Returns the current database ctype.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 240 def ctype query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA") end

current_database()

Returns the current database name.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 220 def current_database query_value("SELECT current_database()", "SCHEMA") end

current_schema()

Returns the current schema name.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 225 def current_schema query_value("SELECT current_schema", "SCHEMA") end

drop_schema(schema_name, **options)

Drops the schema for the given schema name.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 269 def drop_schema(schema_name, **options) execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE" end

encoding()

Returns the current database encoding format.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 230 def encoding query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA") end

exclusion_constraints(table_name)

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

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 663 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_keys(table_name)

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 584 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)

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 633 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()

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 629 def foreign_tables query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA") end

index_name_exists?(table_name, index_name)

Verifies existence of an index with a given name.

Source: show | on GitHub 

# 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

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 768 def remove_exclusion_constraint(table_name, expression = nil, **options) excl_name_to_delete = exclusion_constraint_for!(table_name, expression: expression, **options).name remove_constraint(table_name, excl_name_to_delete) end

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 823 def remove_unique_constraint(table_name, column_name = nil, **options) unique_name_to_delete = unique_constraint_for!(table_name, column: column_name, **options).name remove_constraint(table_name, unique_name_to_delete) end

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 566 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)

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: show | on GitHub 

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

schema_exists?(name)

Returns true if schema exists.

Source: show | on GitHub 

# 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()

Returns an array of schema names.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 245 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()

Returns the active schema search path.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 286 def schema_search_path @schema_search_path ||= query_value("SHOW search_path", "SCHEMA") end

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 278 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)

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 311 def serial_sequence(table, column) query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA") end

unique_constraints(table_name)

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

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 697 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, pg_get_constraintdef(c.oid) AS constraintdef 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) nulls_not_distinct = row["constraintdef"].start_with?("UNIQUE NULLS NOT DISTINCT") deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"]) options = { name: row["conname"], nulls_not_distinct: nulls_not_distinct, deferrable: deferrable } UniqueConstraintDefinition.new(table_name, columns, options) end end

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.

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 926 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)

Validates the given constraint.

Validates the constraint named constraint_name on accounts.

validate_constraint :accounts, :constraint_name

Source: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 893 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)

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: show | on GitHub 

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 915 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