CMF: a pain in the F

CMS have failed so far: none of them showed the clean code that us, as developers, want in a project.
So, in our company, we switched the S to the F and tried to build a CMF with a primary goal: quality.
The problems we faced were multiple, but the master of them was the persistence layer: let's see where and why we abandoned the relational - and traditional - model in favour of a NoSQL solution, and why, after unsuccesfully trying MongoDB and Redis, we picked a graph database: OrientDB.