Modifying a user-defined type

Adding columns to a user-defined type with the ALTER TYPE command.

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

  ALTER TYPE cycling.fullname ADD middlename text;

  This creates the field metadata and adds the field to the type schema.

  To verify the changes, use DESC TYPE.

  DESC TYPE cycling.fullname ;

  The middle name columns shows in the type definition.

  CREATE TYPE cycling.fullname (
      firstname text,
      lastname text,
      middlename text
  );

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

  ALTER TYPE cycling.fullname 
  RENAME middlename TO middleinitial;

  DESC TYPE cycling.fullname ;

  Shows the new name in the type definition.

  CREATE TYPE cycling.fullname (
      firstname text,
      lastname text,
      middleinitial text
  );