Directed graph based association algebra for object-oriented databases

It has been common knowledge for most researchers that object oriented databases should support relational operations effectively and efficiently, but it has not been resolved adequately. The major reason is that the object oriented data model lacks a solid theoretical foundation, as a relational model does. In order to remedy that problem, the paper presents a directed graph based association algebra that is an important improvement on a non directed graph based association algebra worked out by S.Y.W. Su et al. (1993). An important type of association pattern is introduced as well, which makes the association algebra more practical. The directed graph based association algebra can reflect more precisely the intrinsic quality of the object oriented model and is more advantageous to query processing and optimization of objects than its non directed graph based counterpart.