| From: | "Josh Berkus" <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Nick Haw <nick(dot)haw(at)operagrp(dot)com>, "'pgsql-general(at)postgresql(dot)org'" <pgsql-general(at)postgresql(dot)org>, "'pgsql-novice(at)postgresql(dot)org'" <pgsql-novice(at)postgresql(dot)org>, "'pgsql-novice(at)postgresql(dot)org'" <pgsql-novice(at)postgresql(dot)org>, "'pgsql-novice(at)postgresql(dot)org'" <pgsql-novice(at)postgresql(dot)org> |
| Subject: | Re: [NOVICE] Conditional constraint? |
| Date: | 2002-03-08 18:37:28 |
| Message-ID: | web-821592@davinci.ethosmedia.com |
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| Thread: | |
| Lists: | pgsql-general pgsql-novice |
Nick,
> What I want to do is make a field so that it requires a value after a
> change
> in another field to a particular value. Is this possible with the ADD
> CONSTRAINT command, or will I have to make a custom function and use
> a
> trigger.
That depends on how complicated your rules are. All constraints must
evaluate to a true/false statement, so complex procedures require a
function + trigger instead. How about posting some more details?
-Josh
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