ALTER DOMAIN — change the definition of a domain
ALTER DOMAINname
{ SET DEFAULTexpression
| DROP DEFAULT } ALTER DOMAINname
{ SET | DROP } NOT NULL ALTER DOMAINname
ADDdomain_constraint
ALTER DOMAINname
DROP CONSTRAINTconstraint_name
[ RESTRICT | CASCADE ] ALTER DOMAINname
OWNER TOnew_owner
ALTER DOMAINname
SET SCHEMAnew_schema
ALTER DOMAIN
changes the definition of an existing domain.
There are several sub-forms:
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.
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.
domain_constraint
This form adds a new constraint to a domain using the same syntax as CREATE DOMAIN. This will only succeed if all columns using the domain satisfy the new constraint.
This form drops constraints on a domain.
This form changes the owner of the domain to the specified user.
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.)
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.
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;