> From: Andreas Joseph Krogh <andr...@visena.com> >To: pgsql-hackers@postgresql.org >Sent: Wednesday, 27 May 2015, 13:55 >Subject: Re: [HACKERS] Triggers on transaction? > > >På onsdag 27. mai 2015 kl. 12:42:29, skrev Marko Tiikkaja <ma...@joh.to>: >On 5/27/15 12:39 PM, Jordan Gigov wrote: >>> I found myself in need of triggers that are run only once per transaction, >>> rather than per row or statement within the transaction. Meaning it will >>> always be deferred and never called twice for the same transaction. >> >>What's the use case? > > >I've often needed this for stuff like: > >UPDATE some_table SET col = 'foo' where id = 1; >UPDATE some_table SET col = 'bar' where id = 1; > >I want the "on-tx"-trigger to only run once, and on the last update of "col" >so that it sees 'bar'. >
I often have similar requirements, and usually end up having to track what's already been updated with a trigger or similar then finally do the work in a deferred trigger. I'd have thought something more like FOR EACH { ROW | STATEMENT } PER TRANSACTION would be more fitting. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers