RE: Storing of Serial Number

The Guide to SQL Syntax. See CREATE SEQUENCE statement. Art S. Kagel ----- Original Message ----- From: Dirk Moolman <DirkM@mxgroup.co.za> At: 3/ 8 8:51 > Which manual will tell me more about sequences ? > > > -----Original Message----- > From: owner-informix-list@iiug.org [mailto:owner-informix-list@iiug.org] > On Behalf Of Art S. Kagel > Sent: 08 March 2005 12:52 AM > To: informix-list@iiug.org > Subject: Re: Storing of Serial Number > > nobody wrote: > > > > > > Art S. Kagel wrote: > > > >> Andrew Hamm wrote: > >> > >> Well put Andrew. There is NO defensible<SP?> reason to peak at the > >> next serial value in application code. The practice is a recipe for > >> disaster. > >> > >> Art S. Kagel > > > > > > Well sort of... > > > > Suppose you wanted to create an order entry where you knew the order > > number at the start of the order... (And yes, there are reasons for > > this...) > > Truly, but then SERIAL/SERIAL8 is not the answer for such an order > number. > > > But then again, I wouldn't recommend a serial number, but possibly a > > stored procedure or some code within the app to generate it. Like > those > > 6 - 8 character strings used by reservation systems as locator codes. > > > The sequences in IDS 9.4+ are ideal for this. And I've simulated that > as > you suggest in your other posting using a simple table with a single row > > that I SELECT next_id .... FOR UPDATE, UPDATE next_id = next_id + 1 ..., > > COMMIT to get the next order number. I think I'd use sequences for that > now. > > Art S. Kagel sending to informix-list