Re: a little suggestion on DB

On Fri, 2002-11-22 at 21:00, Pablo Enrique Roman Asenjo wrote: > Dear pear-designers, > > In order to have a very flexible library, i have one observation on DB > nextId() function: > If you build a system in mysql using auto_increment pk, then you perform all > insert using last_insert_id(). It could be greater to generalize the nextId > function to report the last_insert_id() if it is the case of mysql and the > argument is empty. > That could simplify a lot of migration stuff from one database to another. Actually, it is the other way around :-) In for example Oracle, you may request the current value of a sequence with "sequence.currval", but you have no guarantee that some other process is doing the same thing at the same time and getting the same id. Because of this we _always_ request the _next_ key, which is an atomic operation. The value is incremented before it is fetched, and it is protected so that other processes must wait until the increment/read is done before doing their own increment/read. - Stig