RE: transaction locking

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Hi, 

Aleks Kalynovych wrote:
> I have a couple forms that generate a unique ID based on taking
> the highest
> number in the ID column adding 1 to its value. The problem is that I
> donât save that number until the form is submitted. If 2 or more
> persons fill out
> the form at the same time they all get the same
> ID number.  I hope that there are some suggestions on how to
> accomplish this
> with a better method

You really should avoid using this method precisely because of the concurrency issue that will invariably happen. If you're using MySQL and your ID field is of type AUTO_INCREMENT then you can use MySQL built-in method named: LAST_INSERT_ID() or in PHP you can use a function named: mysql_insert_id()

http://www.php.net/mysql_insert_id

For more information visit:
http://www.mysql.com/doc/en/example-AUTO_INCREMENT.html

This is concurrency safe so you shouldn't have this problem in the future.

HTH

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