title: When to use MongoDB or other document oriented database systems?
body: <p>We offer a platform for video- and audio-clips, photos and vector-grafics. We started with MySQL as the database backend and recently included <a href="http://www.mongodb.org/display/DOCS/Home" rel="noreferrer">MongoDB</a> for storing all meta-information of the files, because MongoDB better fits the requirements. For example: photos may have <a href="http://en.wikipedia.org/wiki/Exchangeable_image_file_format" rel="noreferrer">Exif</a> information, videos may have audio-tracks where we to want to store the meta-information of, too. Videos and vector-graphics don't share any common meta-information, etc. so I know, that MongoDB is perfect to store this unstructured data and keep it searchable.</p>
  
  <p>However, we continue developing our platform and adding features. Now one of the next steps will be providing a forum for our users. The question that now arises is: use the MySQL database, which would be a good choice for storing forums and forum-posts, etc. or use MongoDB for this, too?</p>
  
  <p>So the question is: when to use MongoDB and when to use a RDBMS. What would you take, mongoDB or MySQL, if you had the choice and why would you take it?</p>