Обсуждение: How to NOT perform an insert

Can I prevent an insert based on what is in a particular field?

For example, I use PostgreSQL as the backend for my syslog servers and
would like to log when some one makes a configuration change but not
when an ICMP echo request has been denied by the os. I think a function
/ trigger combination can do this but I'm not sure.

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"Fontenot, Paul" <Paul.Fontenot@bannerhealth.com> writes:
> Can I prevent an insert based on what is in a particular field?

Yeah, a BEFORE INSERT trigger can cause the insertion to be skipped
--- just return NULL, instead of returning the row to insert as you'd
normally do.

            regards, tom lane