Getting next auto increment value in MySQL

The: 28/09/2008 - AT: 9:10

My old method of getting the last inserted ID was insecure, atleast when it comes to scripts with concurrent users.

Many developers are incorrectly performing a select query, to get the auto_increment value. And then they add one to the value returned. We however cant rely on this, since it isn't 100% certain that we get the number we want/expect.

So what we can do, is use the mysql_insert_id function of PHP on out database link, (aka connection).

// Getting Last Inserted Row

$last_inserted_row = mysql_insert_id($dblink);

To return the last inserted row, which was inserted by the given connection.

The $dblink is unique to the running script, this should make it impossible to get the wrong id returned, in case another user inserted a row in the middle.

We simply update the Temp-row, including the now known auto_increment value in whatever field we need it. (In my case the filename field, which is my reference to the uploaded file).

I'm currently working on a photogallery for my Blog, where i needed to know the last inserted Id, so i easily could assign the uploaded files a unique value.

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Author: BlueBoden