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POHow do I use MySQL transactions in PHP?
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  1. POHow do I use MySQL transactions in PHP?
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    copied!<p>I'm sorry, this is a very general question but I will try to narrow it down.</p> <p>I'm new to this whole transaction thing in MySQL/PHP but it seems pretty simple. I'm just using mysql not mysqli or PDO. I have a script that seems to be rolling back some queries but not others. This is uncharted territory for me so I have no idea what is going on.</p> <p>I start the transaction with <code>mysql_query('START TRANSACTION;')</code>, which I understand disables autocommit at the same time. Then I have a lot of complex code and whenever I do a query it is something like this <code>mysql_query($sql) or $error = "Oh noes!"</code>. Then periodically I have a function called <code>error_check()</code> which checks if <code>$error</code> is not empty and if it isn't I do <code>mysql_query('ROLLBACK;')</code> and <code>die($error)</code>. Later on in the code I have <code>mysql_query('COMMIT;')</code>. But if I do two queries and then purposely throw an error, I mean just set $error = something, it looks like the first query rolls back but the second one doesn't.</p> <p>What could be going wrong? Are there some gotchas with transactions I don't know about? I don't have a good understanding of how these transactions start and stop especially when you mix PHP into it...</p> <p><strong>EDIT:</strong> My example was overly simplified I actually have at least two transactions doing INSERT, UPDATE or DELETE on separate tables. But before I execute each of those statements I backup the rows in corresponding "history" tables to allow undoing. It looks like the manipulation of the main tables gets rolled back but entries in the history tables remain.</p> <p><strong>EDIT2:</strong> Doh! As I finished typing the previous edit it dawned on me...there must be something wrong with those particular tables...for some reason they were all set as MyISAM.</p>
 

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