Hello do you know domains? It is very similar to your proposal.
http://www.postgresql.org/docs/8.2/static/sql-createdomain.html Regards Pavel Stehule 2009/11/23 Caleb Cushing <xenoterrac...@gmail.com>: > So last time I checked this wasn't possible (at least not that anyone > has told me). I'd like to be able to create constraints that aren't > tied to a specific table/column. > > I think that the syntax would look something like this > > CREATE CONSTRAINT empty CHECK (VALUE = '\0' ); > > this should allow us to do thinks like > > CREATE TABLE users ( > username TEXT NOT empty > ); > constraint cannot be part of expression. CREATE OR REPLACE FUNCTION emptystr(text) RETURNS bool AS $$ SELECT $1 <> ''; -- it is SQL not C $$ LANGUAGE sql; CREATE TABLE users( username TEXT CHECK (NOT emptystr(username)), ... p.s. Is it related to ANSI SQL? Regards Pavel Stehule > the example from create domain (modified) is also pretty good > > CREATE CONSTRAINT zip CHECK( > VALUE ~ '^\\d{5}$' > OR VALUE ~ '^\\d{5}-\\d{4}$' > ); > > -- > Caleb Cushing > > http://xenoterracide.blogspot.com > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
