I have been using this set of functions to do sequences, especially for tables where AUTO_INCREMENT can be inconvenient. Maybe it will help you over just incrementing the ID by 1 in your code.
I based them on the DBIx::MysqlSequence perl module http://brazil.addictmud.org/wiki/index.php/MySQL_Sequences I'd also welcome any criticisms on it if anyone else is bored enough to check it out. Dan. -----Original Message----- From: Dan Buettner [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 27, 2006 8:55 AM To: balaraju mandala Cc: mysql@lists.mysql.com Subject: Re: concurrency problem Use a transaction and an InnoDB table. http://dev.mysql.com/doc/refman/5.0/en/transactional-commands.html Or, use the LOCK TABLES command: http://dev.mysql.com/doc/refman/5.0/en/lock-tables.html An ideal solution (in my mind) is to use a stored procedure to read the table, increment the current value, update the table, and return the new UID to the caller - all inside a transaction. Used to do this with Sybase all the time; never tried it with MySQL's transactions and stored procedures, but don't know why it wouldn't work. Dan balaraju mandala wrote: > Hi Comunity, > > I am facing concurrency problem. The scenario is, I have a table, the > primary key of that table say 'uid' is a unique number, which is used by my > application. So every time i fire a query, i get max(uid) i read this > ResultSet from my Java application. I increament this uid to +1. This > resulted 'uid' will be updated to the Table. This table is used by more > than > one thread at any given time. So if some threads fire SQL command at same > time, they are getting same uid and result is a duplicate values Exception. > I cannot use AUTOINCREMENT. Please anybody have any solution for this? > -- Dan Buettner -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] ----------------------------------------------------------------------------------------------------------------------- This e-mail transmission is strictly confidential and intended solely for the person or organization to whom it is addressed. It may contain privileged and confidential information and if you are not the intended recipient, you must not copy, distribute or take any action in reliance on it. If you have received this e-mail in error, please notify the sender as soon as possible and delete the e-mail message and any attachment(s). This message has been scanned for viruses by TechTeam's email gateway. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
