ALTER TYPE

Function

ALTER TYPE modifies the definition of a type.

Syntax

• Modify a type.

  1 2 3 4 5 6 7 8 9 10 11 12

  ALTER TYPE name action [, ... ] ALTER TYPE name OWNER TO { new_owner | CURRENT_USER | SESSION_USER } ALTER TYPE name RENAME ATTRIBUTE attribute_name TO new_attribute_name [ CASCADE | RESTRICT ] ALTER TYPE name RENAME TO new_name ALTER TYPE name SET SCHEMA new_schema 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 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 ]

• Add a new attribute to a composite type.

  1	ALTER TYPE name ADD ATTRIBUTE attribute_name data_type [ COLLATE collation ] [ CASCADE | RESTRICT ]

Parameter Description

• name

  Specifies the name of an existing type that needs to be modified (schema-qualified).

• new_name

  Specifies the new name of the type.

• new_owner

  Specifies the new owner of the type.

• new_schema

  Specifies the new schema of the type.

• attribute_name

  Specifies the name of the attribute to be added, modified, or deleted.

• new_attribute_name

  Specifies the new name of the attribute to be renamed.

• data_type

  Specifies the data type of the attribute to be added, or the new type of the attribute to be modified.

• new_enum_value

  Specifies a new enumerated value. It is a non-empty string with a maximum length of 64 bytes.

• neighbor_enum_value

  Specifies an existing enumerated value before or after which a new enumerated value will be added.

• existing_enum_value

  Specifies an enumerated value to be changed. It is a non-empty string with a maximum length of 64 bytes.

• CASCADE

  Determines that the type to be modified, its associated records, and subtables that inherit the type will all be updated.

• RESTRICT

  Refuses to update the association record of the modified type. This is the default.

  

  • ADD ATTRIBUTE, DROP ATTRIBUTE, and ALTER ATTRIBUTE can be combined for execution. For example, it is possible to add several attributes or change the types of several attributes at the same time in one command.
  • Only type owners can run ALTER TYPE. To modify the schema of a type, you must also have the CREATE permission for the new schema. To modify the owner of a type, you must be a direct or indirect member of the new owner and have the CREATE permission for the schema of this type. (These restrictions ensure that the ALTER owner will not do anything that cannot be done by deleting and rebuilding the type. However, system administrators can modify the ownership of any type in any way.) To add an attribute or modify the type of an attribute, you must also have the USAGE permission for this type.

Examples

Create an example composite type test, enumeration type testdata, and user user_t.

1
2
3

CREATE TYPE test AS (col1 int, col text);
CREATE TYPE testdata AS ENUM ('create', 'modify', 'closed');
CREATE USER user_t PASSWORD '{Password}';

Rename the data type.

1

ALTER TYPE test RENAME TO test1;

Change the owner of the user-defined type test1 to user_t.

1

ALTER TYPE test1 OWNER TO user_t;

Change the schema of the user-defined type test1 to user_t.

1

ALTER TYPE test1 SET SCHEMA user_t;

Add the f3 attribute to the test1 data type.

1

ALTER TYPE user_t.test1 ADD ATTRIBUTE col3 int;

Add a tag value to the enumeration type testdata.

1

ALTER TYPE testdata ADD VALUE IF NOT EXISTS 'regress' BEFORE 'closed';

Rename a tag value of the enumeration type testdata.

1

ALTER TYPE testdata RENAME VALUE 'create' TO 'new';

Helpful Links

CREATE TYPE, DROP TYPE