In this recent post to his blog Thilanka Kaushalya shows how to use transactions in MySQL databases (using mysqli

Web applications are more popular today than ever with the increasing number of internet users. Most of the standard alone applications converted as web based applications or at least they try to provide a web interface for users. PHP and Mysql are two leading technologies which allow uses on rapid development of web based systems. "Transaction" is a powerful concept which comes with Mysql 4.0 and above versions. Lets explore that.

He introduces the concept of transactions first, providing an example of a bank transfer between two individuals. He uses this to create a simple code sample that turns off the autocommit for the connection (using mysqli_autocommit set to false) and running the SQL in order before the commit. He also includes an example of using the rollback function to return the data back to its original state if there's an error.