A Graphical User Interface for Schema Evolution in an Object-Oriented Database

This paper describes work carried out to prototype a GUI to support schema evolution using class versions. Class versions used for schema evolution require a more sophisticated GUI than schema editors (for schema design), because the database is populated an because support is required to browse and maintain the class versions. Current systems for class versioning require exception handlers or conversion functions to be defined as part of the schema evolution process and thus the GUI must provide support for these operations. A number of desirable properties for such a GUI are discussed and illustrated with examples from the GUI developed by the author.