Object View Hierarchies in DB2 UDB

In this paper, we describe the design and implementation of object views in IBM's DB2 Universal Database system. We first describe the object-oriented aspects of DB2's type system, their implications for views, and our design requirements. We then describe DB2's object view facility, showing its use to create object views of object data and of legacy relational data. We discuss key aspects of its implementation, explaining how the correctness of object view definitions is checked and how we ensure that queries against object views are translated into efficient queries against the underlying stored database. We close by discussing the current status of object views in DB2.