Quoth "Richard Broersma" <[EMAIL PROTECTED]>: > On Mon, Dec 1, 2008 at 8:35 AM, Sebastian Tennant > <[EMAIL PROTECTED]> wrote: >>>> IF (NEW.<column-name> != OLD.<column-name>) THEN ... >>> >>> IF( NEW.* IS DISTINCT FROM OLD.* ) THEN ... >>> >> I sometimes think this kind of gotcha is purposely buried, or not >> addressed at all, in order to force users to read the manual. > > I wouldn't say it is intentionally buried. I would say that the > PostgreSQL manual focuses primarily is on "What are the PG features". > While the manual may at times document some of the good/best practices > to use by combining various PG features, I wouldn't say that its > intention isn't to be an authoritative source on "How to use PG > features." > > On the other hand, there are many ANSI-SQL books that focus on good > practices. For example, the need for the "IS DISTINCT FROM" when > dealing with nulls would be discussed in an SQL book. Once you have > the theory down, you can turn to the PostgreSQL manual to find out how > PostgreSQL implements this functionality.
That's sound advice and I take your point about the manual focussing on Postgre features rather than SQL per se. I have read one or two SQL books but I'm very much a learn by doing person... and the fact is, I haven't done much doing, until now. May I wriggle out a little by saying that I didn't really mean what I said, or rather, I failed to say what I really meant; that it sometimes feels as if a gotcha has been buried in order to make you read the manual. Sebastian -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
