2.1 Data model implementation

The data model implementation is splitted into two distinct layers:

Layer 1

The layer 1 contain the actual in-memory structures that hold the data model contents.

Data model contents (the components of all views: entities, relationships, relations, etc) are structured as objects. This layer offer an uniform interface to manage data model objects.

Layer 2

The layer 2 contain the implementation of the final APIs presented to the rest of the application. Both C and Tcl interfaces are provided.

Each view of the datamodel is implemented in this layer.

Figure 2.2: Data model layers

The rationale of the layer structuration (See Figure 2.2,) of the data model is to ease the introduction of both new data model elements (“objects”) and new views. Every view can use information of any defined data model object type defined on the layer 1.