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ALTER DOMAIN(7)                  SQL Commands                  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
       ALTER DOMAIN name
           DROP CONSTRAINT constraint_name [ RESTRICT | CASCADE ]
       ALTER DOMAIN name
           OWNER TO new_owner
       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
              This  form  adds a new constraint to a domain using the same syntax as CREATE DOMAIN [create_domain(7)].
              This will only succeed if all columns using the domain satisfy the new constraint.

       DROP CONSTRAINT
              This form drops constraints on a domain.

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

       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 priv-
       ilege 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 alter-
       ing 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.

       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_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 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 and SET SCHEMA variants, which are PostgreSQL
       extensions.

SEE ALSO
       CREATE DOMAIN [create_domain(7)], DROP DOMAIN [drop_domain(7)]



SQL - Language Statements         2014-02-17                   ALTER DOMAIN(7)