[EMAIL PROTECTED] (scott.marlowe) wrote in message
news:[EMAIL PROTECTED]...
On 21 Nov 2002, Rod Taylor wrote:
On Thu, 2002-11-21 at 15:09, scott.marlowe wrote:
On 21 Nov 2002, Rod Taylor wrote:
On Thu, 2002-11-21 at 14:11, Bruce Momjian wrote:
Of course, those would be SQL purists who _don't_ understand
concurrency issues. ;-)
Or they're the kind that locks the entire table for any given insert.
Isn't that what Bruce just said? ;^)
I suppose so. I took what Bruce said to be that multiple users could
get the same ID.
I keep having developers want to make their own table for a sequence,
then use id = id + 1 -- so they hold a lock on it for the duration of
the transaction.
I was just funnin' with ya, but the point behind it was that either way
(with or without a lock) that using something other than a sequence is
probably a bad idea. Either way, under parallel load, you have data
consistency issues, or you have poor performance issues.
I'm not familiar with these SQL purists (perhaps the reference is to
J. Celko?) but the fact is that it's hard to call SEQUENCE
product-specific now that it's in Oracle, DB2, and SQL:2003. The
syntaxes do differ a little, usually due to choice of abbreviation,
but as far as I can tell the internals are similar across
implementations.
Peter Gulutzan
Author of Sequences And Identity Columns
(http://dbazine.com/gulutzan4.html)
---(end of broadcast)---
TIP 4: Don't 'kill -9' the postmaster
