I use ADODB currently (http://php.weblogs.com/ADOD😎. I've tested it with MySQL and Postgres.
DB's Supported:
MySQL, PostgreSQL, Interbase, Oracle, MS SQL 7, Foxpro, Access, ADO, Sybase and generic ODBC
Additional Key Features:
- Fairly decent metatypes conversions (not used much by myself)
- Some integrated SQL->HTML support.
- PHP4 Session support
Possible Issues:
- Using sessions requires at least 3 separate includes, this might slow down the script.
- Some DB's do not support some of the methods as the DB does not support the given function. ADODB tries to emulate these options whenever possible, but this may come at a performance loss.
FYI: I have found the most difficult task in providing cross-DB integration is the creation of the base schema in each DB. If anyone has some good tools for creating cross-DB creation or conversion scripts I would greatly appreciate it. I believe ADODB may provide this in its MetaType functionality, but this is yet to be tested in my app.