Defining views in the Binary Relationship Model

摘要

The Binary Relationship Model has been praised for the way it not only supports, but practically forces us to model the “deep structures” of the information in the conceptual schema. An adverse effect is that the conceptual schema becomes very large. This, combined with the fact that a Binary Relationship Model schema gives a “flat” representation of the information, makes it very hard to distinguish important concepts of a model from its less important details. Furthermore, the length of DML statements is directly proportional to the size of the schema. What we need for practical applications is a way of keeping the “deep structures” while seeing only the “surface structures”. We need to be able to define views on a conceptual schema. We need to be able to select and derive from the conceptual schema precisely the concepts we are interested in for each application of our model.We propose two new concepts for view definition in the Binary Relationship Model, DOTs and shortcuts. DOTs are dervied object types and shortcuts are derived roles which are used in the definition of derived binary relationship types.