How can I implement commit/rollback for MySQL in PHP?

Question

Well basically I have this script that takes a long time to execute and occasionally times out and leaves semi-complete data floating around my database. (Yes I know in a pe

Answer 1

Take a look at this tutorial on transactions with PDO.

Basically wrap the long running code in:

$dbh->beginTransaction();
...
$dbh->commit();

And according to this PDO document page:

"When the script ends or when a connection is about to be closed, if you have an outstanding transaction, PDO will automatically roll it back. "

So you will lose the transaction that was pending when the script timed out.

But really, you ought to redesign this so that it doesn't depend on the scriipt staying alive.

Answer 2

You need to use InnoDB based tables for transactions then use any library like PDO or MySQLi that supports them.

Answer 3

<?php
//This may help someone....This code commit the transactions
//only if both queries insert and update successfully runs

$mysqli=new mysqli("localhost","user_name","password","db_name");

if(mysqli_connect_errno())
{
    echo "Connection failed: ".mysqli_connect_error();
}
else
{
    $mysqli->autocommit(FALSE);
    $mysqli->query("insert into tblbook (id,cid,book) values('','3','book3.1')");
    echo $q_ins=$mysqli->affected_rows."<br>";
    $mysqli->query("update tblbook set book='book3' where cid='3'");
    echo $q_upd=$mysqli->affected_rows."<br>";

    if($q_ins==1 && $q_upd==1)
    {
        $mysqli->commit();
        echo "Commit<br>";
    }
    else
    {
        $mysqli->rollback();
        echo "Rollback<br>";
    }
}
?>

Answer 4

try
{
    $mysqli->autocommit(FALSE);
    $mysqli->query("insert into tblbook (id,cid,book) values('','3','book3.1')");
    echo $q_ins=$mysqli->affected_rows."<br>";
    $mysqli->query("update tblbook set book='book3' where cid='3'");
    echo $q_upd=$mysqli->affected_rows."<br>";
    $mysqli->commit();
}
catch(PDOException $e)
{
    $mysqli->rollback();
    echo $sql . '<br />' . $e->getMessage();
}