Josh Berkus wrote: > > Bruce, Richard, > > > Triggers are mostly for testing/modifying the row being > > inserted/updated, while rules are better for affecting other rows or > > other tables. > > Hmmm. Thought that there were also some other criteria: > > 1) Rules can't use indexes to do their processing, so Rules which query large > secondary tables can be a bad idea (maybe this has changed?)
I don't think this is true. Rewrite is before optimizer so it should be optimized just the same. > > 2) Only Rules can "DO INSTEAD"; thus, only Rules are good for defining > Read/Write views. True. > 3) There are no AFTER Rules, making, for example, a rule with a table check on > the new data impractical, so you'd want to use Triggers or Constraints We have changed ordering in 7.3 where I think INSERT rules are _after_ the insert. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
