Implementation Experience with Building an Object - Oriented ViewManagement System

Although views have been found to be important mechanisms for database systems, currently no commercially available OODBMS supports view management tools. There are many challenging problems related to view management that must be adressed in the context of object-oriented models: what features are required to support a view system, how to provide updatable views, and how to utilize the complexity of the object-oriented data model for view deenition (such as behavioral customization, view hierarchy manipulation , and incorporating virtual classes into a consistent global schema). We solve all of these problems in our implementation of the MultiView view management system, which supports updatable views on top of the GemStone OODBMS. The resulting system preserves the functionality of the underlying commercial OODBMS while adding view mechanisms and the features needed to support the view system. Our implementation is general purpose { we provide generic classes deened in Smalltalk that can easily be ported to other OODBMS systems. Program. We are also grateful for support from the 1993 NASA Graduate Student Researchers Program.