How database looks inside?

Eloquera Database is a free closed source product. Eloquera Database as per design and per corporate roadmap targets enterprise level market, not an embedded applications.
We were asked a numerous times about database internals, though we cannot disclose internal API or source code we can provide with a general overview how database looks inside.
Keep in mind that below picture intends to give an overall idea only. Database is a complex product, with a number of patents pending and with sophisticated logic inside, which is very hard to describe in one picture.