Perl-like DBI and generic SQL

I read once on this list that PHP supports a DBI-like database access object (such as the one in Perl). Is this true? Does anyone know where I can find documentation for it? I can't seem to find it in the manual. Also, how do you all handle generic SQL for multiple DBMSs? I'd like (ideally) to write SQL that is DBMS-independent, although that's probably not possible. I'm very familiar with mysql and not much else; as far as I'm aware, mysql is the primary DBMS that has problems with standard SQL (like nested queries and such). Does anyone even worry about this? I'm writing a little piece of software that I'd like to be as extensible as possible and as usable as possible for people using any DBMS, including mysql. Anyway, if I can't find a generic built-in database interface in PHP, it'll all be moot. I'd really rather not use phplib; I'd like to use an interface built in to the interpreter rather than something that's interpreted on every page access. Thanks for the help. Dean.