Alter a user-defined type (UDT)

Use the ALTER TYPE command to add fields to a user-defined type (UDT) or to rename an existing field in a UDT.

Restriction: Modifying UDTs used in primary keys or index columns are not supported. Changing the field type is not supported.

Prerequisites

Add a middlename field of type text to the user-defined type cycling.fullname.

ALTER TYPE cycling.fullname
ADD middlename text;

The ALTER TYPE command adds the field to the type.

Verify the changes, use the DESC TYPE command:

DESCRIBE TYPE cycling.fullname;

Results

The middlename column appears in the type definition.

To change the name of an existing field, use RENAME.

ALTER TYPE cycling.fullname
RENAME middlename TO middle
  AND lastname TO last
  AND firstname TO first;

Verify the changes.

DESCRIBE TYPE cycling.fullname;

Results

The renamed fields appear in the type definition.