EFFICIENT IMPLEMENTATION OF TYPED VIEW HIERARCHIES FOR ORDBMS

摘要

A method for typed view hierarchies for an object-relational database management (ORDBMS). The views in the hierarchy are merged into a unified hierarchy vie w through case expressions for mapping and wrapping of overloaded columns. During the merge , the underlying logical tables are eliminated which results in a simplified query graph. The transformation is a non- loss operation which condenses the type information within the case expressions. This allows update, delete and insert operations to be resolved on the query graph on a local level. Using query rewrite rules, the case expressions may be simplified further.