Hi, there's very much information about how transactions and locking works in InnoDB, but maybe there's also a simple and understandable answer to my simple question:
When I start a transaction, then find the maximum value of a column and use that + 1 to write a new row into the table, how do transactions protect me from somebody else doing the same thing so that we'd both end up writing a new row with the same value? Here's a description: BEGIN TRANSACTION new_id := (SELECT MAX(id) FROM table) + 1 -- some more work here INSERT INTO table (id, ...) VALUES (new_id, ...) COMMIT What happens if another user does the same in that "more work" region? (Of course, this example is pseudocode, I really have a PHP application that does this.) -- Yves Goergen "LonelyPixel" <[EMAIL PROTECTED]> Visit my web laboratory at http://beta.unclassified.de -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
