On 2013-11-19 12:45:27 -0800, Josh Berkus wrote: > On 11/19/2013 08:42 AM, Andres Freund wrote: > > Could you explain a bit what the use case of this is and why it's not > > sufficient to allow constraint triggers to work on a statement level? > > "Just" that there would be multiple ones fired? > > The main reason is to enforce arbitrary assertions which need > enforcement at the end of a transaction and not before. For example: > [...] > You can't enforce this at the statement level because the > update/insert/deletes can happen in any order on the various tables.
That's why I suggested adding statement level constraint triggers (should be a farily small patch), which can be deferred till commit. The problem there is that they can be triggered several times, but that can relatively easily accounted for in user code. I can't really say why, but commit time even triggers make me nervous... Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
