- IF EXISTS
Do not throw an error if the domain does not exist. A notice is issued in this case.
The name (optionally schema-qualified) of an existing domain.
Automatically drop objects that depend on the domain (such as table columns), and in turn all objects that depend on those objects (see Section 5.13).
Refuse to drop the domain if any objects depend on it. This is the default.
This command conforms to the SQL standard, except for the IF EXISTS option, which is a PostgreSQL extension.