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ALTER
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 may 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(5)].  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 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.

  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.

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(5)], DROP DOMAIN [drop_domain(l)]

Index for Section DOMAIN

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