A Graphical Schema Representation for Object-Oriented Databases

Abstract

The graphical representation of database schemata has been a useful tool for the designers and users of database systems. Such a tool is no longer viewed simply as a convenience, but as a necessity. In this paper, we present a graphical schema representation for object-oriented databases (OODBs) which incorporates a wide variety of symbols including those for classes, attributes, methods, user-defined relationships, constraint relationships, and generic (system-defined) relationships—enough to support a diverse group of object-oriented data models. We have also defined several levels of abridgement or display, one of which allows the user to display only the class hierarchy. The OOdini system that creates and manipulates such graphical schemata is discussed. This system, besides offering constraint-based editing of the aforesaid schema representation, provides for conversion into an abstract OODB schema language. A feature is also provided for converting this abstract textual language into the syntax of the Vodak Modeling Language, thus making OOdini an effective OODB graphical interface.