Vlad Romascanu <vromascanu@xxxxxxxxxxx> writes: > Hi, Tom, > Why does: > CREATE CAST (text AS bytea) WITHOUT FUNCTION; > SELECT E'C:\\something'::text::bytea; > work as expected, but (with the original text->bytea cast in place): > CREATE DOMAIN my_varlena AS text; > CREATE CAST (my_varlena AS bytea) WITHOUT FUNCTION; > SELECT E'C:\\something'::my_varlena::bytea; > does not Domains are not meant to support ad-hoc cast paths like that --- generally, the parser smashes domains to their base types before even looking into pg_cast. The reason for this is that the defined pathway is source_domain -> source_base_type -> dest_base_type -> dest_domain and allowing user-defined cast paths to short-circuit that would create all kinds of uncertainty, in particular whether or not constraints on a destination domain had been verified. Possibly we ought to disallow CREATE CAST involving a domain, since you're not the first person to think that he can impose special cast rules by using a domain. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
