> No, I am not referring to this "Primary Key Sequence Generated By Bean > Self Cache" thread on TSS. > > I am referring to the pattern discussed in "EJB Design Patterns" book by > "Floyd Marinescu". > > I agree that JDBC would suffice but then we need to use "SELECT MAX(COL) > FOR UPDATE" which locks the table and if > The transaction is a long one then it is a potential bottleneck.
no - dont do that for the reasons you indicate. Instead use a sequence, or other database generated number (my opinion). given the current options, this is my preferred choice - and you will not incur the cost of locking the table. (note here that a sequence is a vendor specific thing). cheers dim > > Thanks, > Saroj > > -----Original Message----- > From: Dmitri Colebatch [mailto:[EMAIL PROTECTED]] > Sent: Friday, September 06, 2002 12:38 PM > To: [EMAIL PROTECTED] > Subject: Re: PK Generator > > > > Hi Dmitri, > > Hi (o: > > > Pls. excuse me this off the list post. > > hmmmm, grrrrr... yes... well... normally, I frown on this sort of > stuff.... > ejb-interest is good for this sort of question... > > but seeing as its friday afternoon and I'm in a good mood (o: > > > I am trying to use the Sequence Block PK Generation Strategy for my > CMP. > > never heard of it by name... are you referring to this - > http://www.theserverside.com/patterns/thread.jsp?thread_id=5285 ? > > > Did you use it? Any pointers?? > > haven't used it. I try to use database sequences where possible for > this > sort of thing. JDBC3 supports pulling the retrieved value out, so ejb > containers will soon be able to do everything in one trip to the > database. > > > Any ideas? > > use a sequence.... most databases have some sort of support, be it real > sequences as in oracle and postgres, or crappy auto-numbers as in db2, > sql > server.... > > I generally do a query first to get the sequence nextval, and then do my > insert. > > hth > dim > > ps - next time, post this sort of thing to a mailing list > ([EMAIL PROTECTED]) > > > > =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
