On Sat, Feb 02, 2008 at 05:23:39PM -0500, Christopher Browne wrote: > On Feb 2, 2008 2:43 PM, David Fetter <[EMAIL PROTECTED]> wrote: > > It still involves DDL-like operations in the sense of changing > > (for the duration of the query) trigger behavior. > > But that "change of trigger behavior" is still more in the "DML" > sense than "DDL sense." > > The point of TRUNCATE is that we have an optimization that's > superior (in some important senses) to "DELETE FROM." > > The differences between TRUNCATE FOO and DELETE FROM FOO do not have > to do with the one altering the schema for the table. The schema > remains the same.
In essence, the schema changes for the duration of the TRUNCATE. Any data integrity constraints that triggers used are therefore violated, and it's DDL-like. To put it another way, if you want to duplicate the trigger-suppression behavior, you have to issue DDL. > I think it would be nice to be able to have more "trigger hooks" > relating to DDL changes, but I also think that will represent some > fundamentally more difficult problems being raised than is the case > for a TRUNCATE trigger. Are they really? Cheers, David. -- David Fetter <[EMAIL PROTECTED]> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: [EMAIL PROTECTED] Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate ---------------------------(end of broadcast)--------------------------- TIP 1: 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
