Andrew Winkler <the_andrew_winkler(at)yahoo(dot)com> writes:
> postgres=# create type complex as (r numeric, i numeric);
> CREATE TYPE
> postgres=# create domain unitary as complex;
> ERROR: "complex" is not a valid base type for a domain
> Are composite types not useable for domains?
Nope, sorry. We currently only support domains over base types.
I don't think anyone's even thought about doing the above, though
it does seem like a potentially useful thing.
regards, tom lane