[Boost-users] C++ Framework Libraries for Programming Popular databases

I am interested in your recommendation of any open source, cross-platform C++ libraries designed for programming the major databases (Oracle, MySql, Postgres, MS Access, Sybase, etc). Boost does not provide any such database/sql library framework for C++. If you can point me toward a source or sources that do offer such a framework, and possibly one(s) the Boost people favor, it would be very much appreciated. Primarily, I am developing code for Windows and Unix/Linux.