The relationship between semantic data models and objectoriented database systems is examined. In particular, it is described how the Aspect Project has taken a semantic data model (the extended relational model RM/T) and, with the addition of an abstraction mechanism, moved towards providing an objectoriented database as the basis of an integrated project support environment ( IPSE).
databases, semantic' data models, object-oriented databases, IPSE, abstraction model
Current database research spans a large number of areas. However, two strands of work are of particular note, One is the investigation and defininition of new data models to support existing database applications. The main trust of this work is to define more expressive data models through which it is possible to represent more accurately the application domain. The second strand concerns the application of database technology to design applications where the characteristics of the application make the use of traditional database techniques particularly difficult. The ability to record the behaviour of objects in the application domain through close coupling of data structures with the operations that effect them seems to be the key approach here.
However, these two areas of work are not disjoint. There are a number of similarities of approach that allow comparisons to be made between them. In this paper this relationship is explored with particular reference to work carried out by the Aspect project, where, as part of a large project aimed at the development of an integrated project support environment (IPSE), a decision was made to undertake an implementation of the semantic data model RM/T as its basis, and through the addition of an