George Young wrote: > Since foreign keys per se can't do this, I presume the way > is to use triggers, though I have not used triggers before.
Says who? Just don't specify NOT NULL on the referencing column. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
