如何在mysqli中开始和结束交易？

据我所知，事务在调用语句后开始，在调用命令后结束，如下面的示例所示。$mysqli->autocommit(FALSE);$mysqli->commit();

<?php
//Start transaction 
$mysqli->autocommit(FALSE);
$mysqli->query('UPDATE `table` SET `col`=2');
$mysqli->query('UPDATE `table1` SET `col1`=3;');
$mysqli->commit();
//End transaction

//Executing other queries without transaction control
$mysqli->query("Select * from table1");
$mysqli->query("Update table1 set col1=2");
//End of executing other queries without transaction control

//Start transaction 
$mysqli->autocommit(FALSE);
$mysqli->query('UPDATE `table` SET `col`=2');
$mysqli->query('UPDATE `table1` SET `col1`=3;');
$mysqli->commit();
//End transaction
?>

我理解正确了吗？如果不能，请纠正我，因为这实际上是我第一次在现实生活中使用交易。

谢谢。