This way of generating auto increment keys doesn't work without table locks. There are many discussions of how to generate keys, I suggest you find one and use a more reliable method.
david jencks On 2002.03.05 18:00:43 -0500 Christine wrote: > Hi, The reason I have this issue is because I am actually implementing > the > auto_increment by myself. The whole store is: > I have a table with an integer type unique ID. everytime, when I create a > new > EJB object, I call the finderMaxID method to get the MAX ID, then MAX ID > + 1 to > get the new max id and create a new EJB object. at the same time, insert > a new > record to the table. In the whereclause for the finderMaxID, i used " > WHERE ID > IN (SELECT MAX(ID) FROM Customer)". Now, MySQL doesn't support > sub-select. I > have to use other way to do so. > I am not sure whether I understood what you mean, but how can ORDER BY ID > help? > > Burkhard Vogel wrote: > > > Hi, > > if you are in one table and you have only one line which will be MAX, > you > > could use ORDER BY ID desc . Which will be much faster as well, if in > two > > tables, join them and do the same... But if there are more than one > value... > > Wait for MySQL 4.0 which will support subqueries. > > Regards > > Burkhard > > ----- Original Message ----- > > From: "Christine" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Friday, March 01, 2002 1:12 PM > > Subject: [JBoss-user] Finder Method in JBoss > > > > > Hi, > > > > > > I have a finder method which use sub-select as following: > > > findMaxIDWhereClause : ID IN (SELECT MAX(ID) FROM Customer) > > > it works fine when I used IBM WebSphere and DB2. Now I am switching > to > > > JBoss + Tomcat + MySQL. Cause MySQL doesn't support sub-select. Does > > > anyone know whether there is some other way to get my > > > findMaxIDWhereClause work without have to change code? Thanks in > > > advance! > > > > > > regards, > > > -- > > > Jia (Christine) Li > > > > > > 524N ICT Building > > > Department of Computer Science > > > University of Calgary > > > > > > > > > > > > _______________________________________________ > > > JBoss-user mailing list > > > [EMAIL PROTECTED] > > > https://lists.sourceforge.net/lists/listinfo/jboss-user > > -- > Jia (Christine) Li > > 524N ICT Building > Department of Computer Science > University of Calgary > > > > _______________________________________________ > JBoss-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/jboss-user > > _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
