Relaxing the Instantiation Link: Towards a Content-Based Data Model for Information Retrieval

This is a double scope article. First, we define a structurally object-oriented data model, where objects' structures are richer than those of their classes. This model is intended to be used in applications such as content-based information retrieval, whose particularity is the fact that objects do not have a predefined conceptual structure that can be fully abstracted in a class schema. We thus relax the classical instantiation link between classes and objects, and rebaptize it the "realization" link. Some of the problems that arise because of this relaxation are investigated, especially when it comes to querying the database. We present a query language for the model that respects the realization link. The second aim of the article is to prove that such a model can make use of existing structurally object oriented models for defining and querying the database. Within a classical structured model (the model of Identity Query Language, IQL), we define a meta-level of data, where objec..