A set-oriented method definition language for object databases and its semantics

摘要

In this paper we propose a set-oriented rule-based method definition language for object-oriented databases. Most existing object-oriented database systems exploit a general-purpose imperative object-oriented programming language as the method definition language. Because methods are written in a general-purpose imperative language, it is difficult to analyze their properties and to optimize them. Optimization is important when dealing with a large amount of objects as in databases. We therefore believe that the use of an ad hoc, set-oriented language can offer some advantages, at least at the specification level. In particular, such a language can offer an appropriate framework to reason about method properties. In this paper, besides defining a set-oriented rule-based language for method definition, we formally define its semantics, addressing the problems of inconsistency and non-determinism in set-oriented updates. Moreover, we characterize some relevant properties of methods, such as conflicts among method specifications in sibling classes and behavioral refinement in subclasses.