Thursday, September 19, 2002, 9:31:47 PM, you wrote: DS> He means UPDATE WHERE, which we don't support. The better way it to use DS> SELECT FOR UPDATE, which is supported.
DS> If all you care about is a sequence generator, just use the one included DS> with JBoss. The CMP example code that comes with the Quick Start Guide DS> uses it. Alternatively, you can use the new autonumber code that Alex DS> just added to cvs HEAD. Under JDK1.3 auto-increment for now works only with MySQL. JBossCMP supports database generated keys, but as it uses JDBC3.0 api, JDK1.4 is required. PS: btw, new non-MySQL auto-increment SQL templates are welcome. I just don't the syntax of other databases to set up it. alex DS> -dain DS> Jim Crossley wrote: >> Thank you for all your replies, but I'm still a bit confused WRT something >> Floyd Marinescu writes in his EJB Design Patterns book. In it, he describes >> the concurrency issues involved in a primary key generation pattern that >> involves the use of a Sequence CMP bean. >> >> I think he's saying that I can get away with a READ_COMMITTED isolation level >> (Oracle's default, I believe) if the app server can provide "verified >> updates". I'm not entirely sure what those are, but here's Floyd's >> description: >> >> "Isolation of READ_COMMITTED with application server CMP verified updates. >> In this case, the application server will compare the contents of the >> Sequence entity bean to that in the database before transaction commit time. >> If it is discovered that a previous transaction has already gotten the next >> block, an exception will be thrown. This is an optimistic concurrencty check >> implemented at the application server level, allowing you to use a >> transaction isolation level of just READ_COMMITTED, since the application >> server guarantees consistency." >> >> Does/can JBoss 3.0.x provide this guarantee? >> >> Jim ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
