The GRAS system, developed at the Technical University of Aachen, is a public domain OODB which uses a graph oriented data model. It provides: The graph schemes are similar to CONNEKT's network consistency models (NCMs), in specifying inheritance hierarchies and the syntactic properties of graphs, such as which types of nodes can be connected by each type of edge.

All these features make GRAS almost perfectly suited for use by CONNEKT in PLINTH, but unfortunately it has one limitation: edges are not first-class objects in GRAS, and it is not possible to attach attributes to them, as CONNEKT requires. However, attributed links can be simulated by using nodes to represent links, i.e. instead of node-edge-node chains with a variety of edge types, we would have node-from-linknode-to-node where from and to are the only edge types allowed. The only drawback with this solution is that the built-in graph scheme syntax facilties become much less directly useful to CONNEKT. However, since most OODBs don't even use a graph model at all, GRAS is still a very good candidate for use in PLINTH, and some preliminary experiments with providing a Pop11 API to it have been done already.


Kiesel, N., A. Schuerr and B. Westfechtel (1992): Design and Evaluation of GRAS, a Graph-Oriented Database System for Engineering Applications. Lehrstuhl für Informatik III, Technical University of Aachen.


A.3 Ode

A.4 Kala