This paper extends an object-oriented approach to query processing in a deductive database with the consideration of deductive rules. In the object-oriented approach, each deductive rule and fact is represented as an active object, which acts with its own dedicated control sequences according to its functionality. All operations in objects are proceeded asynchronously. Since no object has global knowledge about the database, cooperation among objects is necessary in answering a query. While most of the conventional search strategies focus on some parts of the AND/OR tree expanded by a query at a time, the object-oriented approach can search down the AND/OR tree with a breadth-first strategy in parallel. As a result, all parts of the tree can be considered globally so that queries do not have to be evaluated in a tuple-by-tuple, operation-by-operation fashion; and the need of maintaining temporary relations can be eliminated.
Implementing an Object-Oriented Deductive Database Using Temporal Reasoning
