Description:
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I don't understand why documenters chose to use autocommit(FALSE) to "start" a transaction rather than begin_transaction(). In fact, turning off autocommit doesn't start a transaction at all in environments where autocommit is off by default (depends on how the DBA configured MySQL). The example would be wiser / safer if it had shown users that it's safer to explicitly start a transaction while possibly turning autocommit off.

http://dev.mysql.com/doc/refman/5.0/en/commit.html describes the behavior of START TRANSACTION, COMMIT and ROLLBACK.

Note that DBAs can turn off autocommit by default setting the autocommit or the init_connect variables in my.cnf/my.ini. In fact, I tell my developers not to assume that autocommit is on or off. I encourage developers to set it the way they want it for their application's needs in their application's DAL setup. That way, assuming it's "the other way" can't come back to bite you. :-)

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From manual page: http://www.php.net/mysqli.commit
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