SET RESTRICTIONS FOR SEMANTIC GROUPINGS

Most research on semantic integrity has taken place in the traditional database fields, specifically the relational data model. Advanced mod els, such as semantic and object-oriented data models, have developed higher level abstractions to increase their expressive power in order to meet the needs of newly emerging application domains. This allows t hem to incorporate some semantic constraints directly into their schem as. There are, however, many types of restrictions that cannot be expr essed solely by these high-level constructs. Therefore we extend the p otential of advanced models by augmenting their abstractions with usef ul set restrictions. In particular, we identify and formulate four of their most common semantic groupings: set groupings, is-a related set groupings, power set groupings, and Cartesian product groupings. For e ach, we define a number of restrictions that control its structure and composition. We exploit the notion of object identity for the definit ion of these semantic restrictions. This permits each grouping to capt ure more subtle distinctions of the concepts in the application enviro nment, as demonstrated by numerous examples throughout this paper. The resulting set of restrictions forms a general framework for integrity constraint management in advanced data models.