Symfony 2 comes with native support to connect to MongoDB using the DoctrineMongoDBBundle. Getting started is quite simple and there is not much that needs to be configured, but the manual does not say how to enable query logging although it is already possible with Symfony PR3. Query logging allows you to debug queries sent to the DB server by writing them in a log file. It is very useful for cases when you issue a query and you are not getting the results you expected.

The key is to add a "logger_class" value into your Symfony configuration file pointing to the "DoctrineMongoDBLogger" tool. The queries will then show up in your normal log files. They include a sample line along with a brief explanation of the values inside.

Part of our business is to develop internal applications and support customers, so we dedicate a good amount of time to research, test and learn new technologies. We have been following this whole movement and decided to give MongoDB a try. What has really taken our attention regarding MongoDB is its simplicity, yet how powerful it is. It lowers the barrier to develop DB-driven applications even more.

They start by explaining how to use MongoDB together with PHP and get both the server and client sides up and running. From there they introduce ODM, a object document mapper from Jon Wage (of the Doctrine project) that lets you easily interact with MongoDB instances. A code sample it provided to show how simple the tool is to use and how it can integrate with symfony as an entity.