В Срд, 18.08.2004, в 04:45, Josh Berkus пишет:
> Hey, I see you figured out a workaround to writing a trigger for this. Let's
> see if we can make it work.
> ERROR: there is no unique constraint matching given keys
> for referenced table "objects"
> The reason for this is that CASCADE behavior gets quite odd when there is an
> FK reference to a non-unique column. We used to allow it, in 7.1, and I was
> responsible for a number of bug reports that led to us disallowing it. It
> should be theoretically implementable and relationally sound but will require
> a *lot* of troubleshooting to make work. So far, nobody's really interested
> However, you have an easy way out:
> ALTER TABLE objects ADD CONSTRAINT obj_unq_2 UNIQUE (name, class_name);
I was worried about the performance hit because (name, class_name) will
always be unique, yet they will be checked for uniqueness.
Markus Bertheau <twanger(at)bluetwanger(dot)de>
In response to
pgsql-sql by date
|Next:||From: Theo Galanakis||Date: 2004-08-18 06:11:55|
|Previous:||From: Joe Conway||Date: 2004-08-18 05:15:59|
|Subject: Re: SQL Challenge: Arbitrary Cross-tab|