Updates and object-generating views in ODBS

摘要

In object-oriented database systems, a view mechanism can extend the object paradigm by adapting object structure and object behavior to the needs of the different applications or users. In this paper we consider views with object-generating semantics which is an important construct in database environment and mediator systems (Y. Papakonstantinou, S. Abiteboul, H. Garcia-Molina, Object Fusion in Mediator Systems, in: Proceedings of the International Conference on Very Large DataBases, New York, July 1998). We reexamine the problem of updating views according to the aspects of object-orientation, namely: object identity, inheritance and aggregation path. Furthermore, we propose a taxonomy of virtual classes in order to define the update semantics with respect to the virtual class semantics. We present also a cost model for our update algorithms to quantify the impact of our materialization method upon updates propagation times.