We offer a platform for video- and audio-clips, photos and vector-grafics. We started with MySQL as the database backend and recently included MongoDB for storing all meta-information of the files, because MongoDB better fits the requirements. For example: photos may have Exif 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.
然而，我们仍在继续开发我们的平台并添加新功能。接下来的步骤之一就是为我们的用户提供一个论坛。现在出现的问题是:使用MySQL数据库，这将是一个很好的选择，存储论坛和论坛帖子等或使用MongoDB，这也是?
所以问题是:什么时候使用MongoDB，什么时候使用RDBMS。如果可以选择，你会选择mongoDB还是MySQL，为什么会选择?
