NEED BOOK: DB Abstaction

Hello, Can anyone here, please, recommend me a good book that covers the DB abstracion that has PHP4? Most of the books only deal with MySQL, and that's not always my choice for a DB administrator. So I need to program scripts that can connect to any DB. I use this in ASP: I write a tiny script that only connects to a DB, and then I include it in any script that needs DB connectivity. Then, If I change the DB, I only change the tiny script, and the rest works just like before. (By the way, is it possible to do this in PHP at all? I believe it is) Please, if you have any books you can recommend Cc to my email address: ereimber@multinet.cl Thanks, Erich Reimberg N