I wrote a simple database library for rapid prototyping some time back, and decided to put it on github for anyone to use. It mainly takes away the need to setup a database structure before being able to save data on a server when writing simple web apps or other client apps.
It is both a PHP library, a server backend, and a javascript library in one. Use it for prototyping only, as it is not made to be neither secure nor efficient. However, once you got your app up and running, it should be easy to exchange those parts, or just make the library more secure.
Feel free to use and feel free to comment or send pull requests. The repo is here.