database abstraction layers [from: MySQL feature/bug]

>I have been crafting my own database abstraction layer, and in doing so >create an array of the results of a query. Is this an db abstraction layer written in php (script), or written as a module for php (C)? I was thinking of writing an (open source) db-abstraction module (that uses existing db-modules, of course), which could then be used from php-script as well as from other modules that need db-functionality without committing to a specific database. Or, does such a module exist already and should I concentrate on using and/or co-developing that one? Thanks, Marc.