ALTER 
DOMAIN(7) 					  PostgreSQL 9.2.7 Documentation					   ALTER DOMAIN(7)

NAME

       ALTER_DOMAIN - change the definition of a domain

SYNOPSIS

       ALTER DOMAIN name
	   { SET DEFAULT expression | DROP DEFAULT }
       ALTER DOMAIN name
	   { SET | DROP } NOT NULL
       ALTER DOMAIN name
	   ADD domain_constraint [ NOT VALID ]
       ALTER DOMAIN name
	   DROP CONSTRAINT [ IF EXISTS ] constraint_name [ RESTRICT | CASCADE ]
       ALTER DOMAIN name
	    RENAME CONSTRAINT constraint_name TO new_constraint_name
       ALTER DOMAIN name
	   VALIDATE CONSTRAINT constraint_name
       ALTER DOMAIN name
	   OWNER TO new_owner
       ALTER DOMAIN name
	   RENAME TO new_name
       ALTER DOMAIN name
	   SET SCHEMA new_schema

DESCRIPTION

       ALTER DOMAIN changes the definition of an existing domain. There are several sub-forms:

       SET/DROP DEFAULT
	   These forms set or remove the default value for a domain. Note that defaults only apply to subsequent INSERT commands; they do not
	   affect rows already in a table using the domain.

       SET/DROP NOT NULL
	   These forms change whether a domain is marked to allow NULL values or to reject NULL values. You can only SET NOT NULL when the columns
	   using the domain contain no null values.

       ADD domain_constraint [ NOT VALID ]
	   This form adds a new constraint to a domain using the same syntax as CREATE DOMAIN (CREATE_DOMAIN(7)). When a new constraint is added
	   to a domain, all columns using that domain will be checked against the newly added constraint. These checks can be suppressed by adding
	   the new constraint using the NOT VALID option; the constraint can later be made valid using ALTER DOMAIN ... VALIDATE CONSTRAINT. Newly
	   inserted or updated rows are always checked against all constraints, even those marked NOT VALID.  NOT VALID is only accepted for CHECK
	   constraints.

       DROP CONSTRAINT [ IF EXISTS ]
	   This form drops constraints on a domain. If IF EXISTS is specified and the constraint does not exist, no error is thrown. In this case
	   a notice is issued instead.

       RENAME CONSTRAINT
	   This form changes the name of a constraint on a domain.

       VALIDATE CONSTRAINT
	   This form validates a constraint previously added as NOT VALID, that is, verify that all data in columns using the domain satisfy the
	   specified constraint.

       OWNER
	   This form changes the owner of the domain to the specified user.

       RENAME
	   This form changes the name of the domain.

       SET SCHEMA
	   This form changes the schema of the domain. Any constraints associated with the domain are moved into the new schema as well.

       You must own the domain to use ALTER DOMAIN. To change the schema of a domain, you must also have CREATE privilege on the new schema. To
       alter the owner, you must also be a direct or indirect member of the new owning role, and that role must have CREATE privilege on the
       domain's schema. (These restrictions enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the
       domain. However, a superuser can alter ownership of any domain anyway.)

PARAMETERS

       name
	   The name (possibly schema-qualified) of an existing domain to alter.

       domain_constraint
	   New domain constraint for the domain.

       constraint_name
	   Name of an existing constraint to drop or rename.

       NOT VALID
	   Do not verify existing column data for constraint validity.

       CASCADE
	   Automatically drop objects that depend on the constraint.

       RESTRICT
	   Refuse to drop the constraint if there are any dependent objects. This is the default behavior.

       new_name
	   The new name for the domain.

       new_constraint_name
	   The new name for the constraint.

       new_owner
	   The user name of the new owner of the domain.

       new_schema
	   The new schema for the domain.

NOTES

       Currently, ALTER DOMAIN ADD CONSTRAINT and ALTER DOMAIN SET NOT NULL will fail if the named domain or any derived domain is used within a
       composite-type column of any table in the database. They should eventually be improved to be able to verify the new constraint for such
       nested columns.

EXAMPLES

       To add a NOT NULL constraint to a domain:

	   ALTER DOMAIN zipcode SET NOT NULL;

       To remove a NOT NULL constraint from a domain:

	   ALTER DOMAIN zipcode DROP NOT NULL;

       To add a check constraint to a domain:

	   ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5);

       To remove a check constraint from a domain:

	   ALTER DOMAIN zipcode DROP CONSTRAINT zipchk;

       To rename a check constraint on a domain:

	   ALTER DOMAIN zipcode RENAME CONSTRAINT zipchk TO zip_check;

       To move the domain into a different schema:

	   ALTER DOMAIN zipcode SET SCHEMA customers;

COMPATIBILITY

       ALTER DOMAIN conforms to the SQL standard, except for the OWNER, RENAME, SET SCHEMA, and VALIDATE CONSTRAINT variants, which are PostgreSQL
       extensions. The NOT VALID clause of the ADD CONSTRAINT variant is also a PostgreSQL extension.

SEE ALSO

       CREATE DOMAIN (CREATE_DOMAIN(7)), DROP DOMAIN (DROP_DOMAIN(7))

PostgreSQL 9.2.7						    2014-02-17							   ALTER DOMAIN(7)