On Sun, 2008-09-21 at 04:38 +0400, Dmitry Koterov wrote: > Is it possible to create a foreign key constraint for ALL elements of > an array field? > > CREATE TABLE a(id INTEGER); > CREATE TABLE b(id INTEGER, a_ids INTEGER[]); > > Field b.a_ids contains a list of ID's of "a" table. I want to ensure > that each element in b.a_ids exists in a in any time. Is it possible > to create an automatic foreign key?
No, its not possible. Need a trigger. I think we should support it though. If we extend the relational model with arrays then it would be sensible if we support this aspect as well. Implementation would be fairly straightforward. ri_triggers currently assumes a non-array value is being checked, but that could be changed to IN(array). Multi-column keys with arrays sound confusing though. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
