fost-schema is the lowest most layer of the OR/M part of Fost 4. It is responsible for handling the abstractions of the databases themselves.

The database abstraction is able to handle both RDBMS systems as well as more exotic database options. This library includes a simple transactional JSON database with minimum features. As well as the database connectivity there are a number of other key areas within the library:

* [[fields]] -- Abstracts the types and storage requirements for logical fields within a database.
* [[models]] -- Handles the description of the object types that are to be storable within the system.
* [[instance]] -- These are the instances that are persisted within the database.

The abstraction layer is able to handle both dynamic models (i.e. the models are defined at runtime, possibly through introspection of an existing database), static models (the models are defined more or less as normal C++ classes with special annotations) and a mixture of the two (static models augmented with dynamic fields).