A View Environment to Reuse Class Hierarchies in an Object-Oriented Database System

Many studies of interactive environments of object-oriented databases are based on extensions to declarative query languages, designed for relational databases. Such environments do not use well the characteristics of the object-oriented databases. In this paper, we introduce an environment that allows users to construct tailored class hierarchies, which represent both the users’ views and the users’ queries to the object-oriented databases. In this environment, users express their queries in the form of class hierarchies. The results of the queries are stored as classes of the tailored class hierarchies. There are three kinds of class hierarchies: original class hierarchies (databases themselves), domain class hierarchies (collections of domains), and tailored class hierarchies (user-made queries). We define the semantics and the constraints of the three kinds of class hierarchies and the basic operations to evolve them, to modify them, to cut them, to copy them, and to paste them.