DSLib offers extensions for the programming with wxWidgets which include universal database abstractions for PostgreSQL, MySQL and SQLite as well as persistence frameworks. It furthermore also offers Containers, libraries for web development, network development and much more. Since this has always been just a project that I started in my free time, there has not really been any documentation. Simply peek into the Header-Data.
I primarily use the DSLib for Warehouse and DynSoft.com as well as many other projects.