Several document-based database systems claim to be schamaless, yet when your data demands cross-document relations (esp. many-to-many), something ugly rears its head which usually ends with you performing multiple queries and relating (or JOINing) data by hand. This essentially forces the work away from the locality and fast speed of the database level, and up towards the remote and slow speed of the client-to-database connection. The difference in speed is akin to the difference between registers and RAM, or between RAM and Disk.

The resultant design pattern often ends up a mirror of what you would have done in any standard SQL database, but without the low level optimizations that a SQL database brings to such a pattern.

Additionally, with a non-native design pattern now in place to deal with your data relationships, concurrency issues may begin to surface.

In SchemafreeDB, your data relationship possibilities are essentially unbounded; yet consistent in both design patterns, access patterns and performance.