MyWebSQL is a web based WYSIWYG Database client written in PHP. It has a simple and intuitive interface with the look and feel of a desktop application, and offers rich features for database management. No installation is needed, just download, extract and you are ready to go. It even has a single file compact version with full functionality, which you can quickly deploy on your server.
Currently MyWebSQL supports working with MySQL, PostgreSQL and SQLite databases.
MongOz is a MongoDB client, intended to be multi-platform. It's written in Java as backend (to handle the MongoDB connections) and Javascript / HTML5 / CSS3 as frontend, in order to have a modern interface, besides being easy to change as desired.