What do I need to do, if anything, to ensure $mdb2->lastInsertID() returns the auto-increment value for that connection?

Question

I've made the switch recently from SQL Server to MySQL, and I can't find a solid enough answer to this question anywhere:

I'm using PHP, MySQL, and the InnoDB table engine on the tables I need to lock. So for a standard series of 3 statements:

1. Insert into table A
2. $id = $mdb2->lastInsertID()
3. Insert into table B (name, fk) VALUES ('foo', $id)

what steps do I need to take to make sure $id has the value of the insert from step 1? Is it fine the way it is? Does everything need to be in a transaction? Do I need to add other queries to lock and release the tables?

Thanks guys.

Answer 1

You should/could, but you don't NEED to do anything: information-functions , function_last-insert-id

The ID that was generated is maintained in the server on a per-connection basis. This means that the value returned by the function to a given client is the first AUTO_INCREMENT value generated for most recent statement affecting an AUTO_INCREMENT column by that client. This value cannot be affected by other clients, even if they generate AUTO_INCREMENT values of their own. This behavior ensures that each client can retrieve its own ID without concern for the activity of other clients, and without the need for locks or transactions.

Answer 2

Better to use transaction if any query fails at least other updates can be rolled back.

OR handle by yourself

If the step 3 fails you will receive error message from mysql store that message in variable and check for that if received delete the record inserted in 1 step.

That is all what transaction handle. You should use transaction.