| PostgreSQL 7.4.8 Documentation | ||||
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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 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.
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.
You must own the domain to use ALTER DOMAIN; except for ALTER DOMAIN OWNER, which may only be executed by a superuser.
The name (possibly schema-qualified) of an existing domain to alter.
New domain constraint for the domain.
Name of an existing constraint to drop.
Automatically drop objects that depend on the constraint.
Refuse to drop the constraint if there are any dependent objects. This is the default behavior.
The user name of the new owner of 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;