Contextualization of OODB Schemas in CROME

Abstract

View mechanisms, widely used in the relational databases, pose new questions in the object model which captures much more semantics. In this paper, we will focus on inheritance and inter-objects relationships, two main semantic aspects of the object model. Like in the relational model, most of the current works about object-oriented views assume a fine granularity of the views. View classes are defined by the application of a query operator to one or two classes of the base schema. View schemas are defined as sets of view classes. These sets are explicitly chosen by the database administrator.

We present the solutions produced by the application of our CROME model. In CROME, view classes extend the descriptions of the domain objects supplied by the base schema. The relationships introduced in the base schema are shared and preserved in view schemas. By adapting them locally, each view schema contextualize these relationships. We will show that this contextualization of the base schema gives it generic properties which enforce a stronger coherence of the view schemas.