table of contents
ALTER TYPE(7) | PostgreSQL 16.1 Documentation | ALTER TYPE(7) |
NAME¶
ALTER_TYPE - change the definition of a type
SYNOPSIS¶
ALTER TYPE name OWNER TO { new_owner | CURRENT_ROLE | CURRENT_USER | SESSION_USER } ALTER TYPE name RENAME TO new_name ALTER TYPE name SET SCHEMA new_schema ALTER TYPE name RENAME ATTRIBUTE attribute_name TO new_attribute_name [ CASCADE | RESTRICT ] ALTER TYPE name action [, ... ] ALTER TYPE name ADD VALUE [ IF NOT EXISTS ] new_enum_value [ { BEFORE | AFTER } neighbor_enum_value ] ALTER TYPE name RENAME VALUE existing_enum_value TO new_enum_value ALTER TYPE name SET ( property = value [, ... ] ) where action is one of:
ADD ATTRIBUTE attribute_name data_type [ COLLATE collation ] [ CASCADE | RESTRICT ]
DROP ATTRIBUTE [ IF EXISTS ] attribute_name [ CASCADE | RESTRICT ]
ALTER ATTRIBUTE attribute_name [ SET DATA ] TYPE data_type [ COLLATE collation ] [ CASCADE | RESTRICT ]
DESCRIPTION¶
ALTER TYPE changes the definition of an existing type. There are several subforms:
OWNER
RENAME
SET SCHEMA
RENAME ATTRIBUTE
ADD ATTRIBUTE
DROP ATTRIBUTE [ IF EXISTS ]
ALTER ATTRIBUTE ... SET DATA TYPE
ADD VALUE [ IF NOT EXISTS ] [ BEFORE | AFTER ]
If IF NOT EXISTS is specified, it is not an error if the type already contains the new value: a notice is issued but no other action is taken. Otherwise, an error will occur if the new value is already present.
RENAME VALUE
SET ( property = value [, ... ] )
See CREATE TYPE (CREATE_TYPE(7)) for more details about these type properties. Note that where appropriate, a change in these properties for a base type will be propagated automatically to domains based on that type.
The ADD ATTRIBUTE, DROP ATTRIBUTE, and ALTER ATTRIBUTE actions can be combined into a list of multiple alterations to apply in parallel. For example, it is possible to add several attributes and/or alter the type of several attributes in a single command.
You must own the type to use ALTER TYPE. To change the schema of a type, you must also have CREATE privilege on the new schema. To alter the owner, you must be able to SET ROLE to the new owning role, and that role must have CREATE privilege on the type's schema. (These restrictions enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the type. However, a superuser can alter ownership of any type anyway.) To add an attribute or alter an attribute type, you must also have USAGE privilege on the attribute's data type.
PARAMETERS¶
name
new_name
new_owner
new_schema
attribute_name
new_attribute_name
data_type
new_enum_value
neighbor_enum_value
existing_enum_value
property
CASCADE
RESTRICT
NOTES¶
If ALTER TYPE ... ADD VALUE (the form that adds a new value to an enum type) is executed inside a transaction block, the new value cannot be used until after the transaction has been committed.
Comparisons involving an added enum value will sometimes be slower than comparisons involving only original members of the enum type. This will usually only occur if BEFORE or AFTER is used to set the new value's sort position somewhere other than at the end of the list. However, sometimes it will happen even though the new value is added at the end (this occurs if the OID counter “wrapped around” since the original creation of the enum type). The slowdown is usually insignificant; but if it matters, optimal performance can be regained by dropping and recreating the enum type, or by dumping and restoring the database.
EXAMPLES¶
To rename a data type:
ALTER TYPE electronic_mail RENAME TO email;
To change the owner of the type email to joe:
ALTER TYPE email OWNER TO joe;
To change the schema of the type email to customers:
ALTER TYPE email SET SCHEMA customers;
To add a new attribute to a composite type:
ALTER TYPE compfoo ADD ATTRIBUTE f3 int;
To add a new value to an enum type in a particular sort position:
ALTER TYPE colors ADD VALUE 'orange' AFTER 'red';
To rename an enum value:
ALTER TYPE colors RENAME VALUE 'purple' TO 'mauve';
To create binary I/O functions for an existing base type:
CREATE FUNCTION mytypesend(mytype) RETURNS bytea ...; CREATE FUNCTION mytyperecv(internal, oid, integer) RETURNS mytype ...; ALTER TYPE mytype SET (
SEND = mytypesend,
RECEIVE = mytyperecv );
COMPATIBILITY¶
The variants to add and drop attributes are part of the SQL standard; the other variants are PostgreSQL extensions.
SEE ALSO¶
CREATE TYPE (CREATE_TYPE(7)), DROP TYPE (DROP_TYPE(7))
2023 | PostgreSQL 16.1 |