I have a field thats called featured its just a true/false but I want to limit it so only 4 entries can be set to true at any given time.

So say I already have 4 items in the database with their featured field set to true. Is there a way to set up that field so that If I inserted a new entry and set it to featured that it would automatically get rid of the oldest featured or would I just have to go about it with php.

I'm just trying to be as lazy as possible and was wondering if there was anything in mysql like that.

thanks for the info..