An Extensible Object-Oriented Database Testbed

This paper describes the object-oriented design and implementation of an extensible schema manager for object-oriented databases. In order to achieve extensibility, we have adopted an open class hierarch y approach using an ob ject-oriented implementation where an object-oriented database maintains its implementation classes as user-defined classes. A Graphical interface for an Object-Qriented database Schema Environment, GOOSE, has been developed. GOOSE supports several advanced features which include schema evolution, schema versioning, and DAG rearrangement view of a class hierarchy. Schema evolution is the ability to make a variety of changes to a database schema without reorganization. Schema versioning is the ability to define multiple schema versions and to keep track of schema changes. A new type of view for object-oriented databases, namely the DAG rearrangement view of a class hierarchy, is also supported.