A formal definition of the Users View (UV) of the Graphical Object Query Language (GOQL)

Abstract

In this paper we provide a brief formal definition of the Users View (UV) of the Graphical Object Query Language(GOQL). The UV provides a graphical representation for object-oriented database schemas and hides from end-users most of the perplexing details of the object-oriented database model, such as methods, hierarchies and relationships. In particular, the UV does not distinguish between methods, attributes and relationships, encapsulates the is-a hierarchy and utilises a number of desktop metaphors to present a graphical schema that is easy to be understood by end-users. Thus, the UV provides the environment, through which end-users, can pose ad-hoc queries through GOQL. We first give a brief formal definition of an object-oriented database schema in the GOQL model. This is given, by providing a formal definition of the basic element of such a schema, namely the class. The UV is then briefly formally defined as a mapping from a GOQL object-oriented database schema. Using this mapping, any object-oriented database schema can be translated into a graphical representation in the UV. The running example of the paper is used to demonstrate the mapping from the textual schema to the graphical schema of the UV. The formal definition of the UV will allow us, in the future, to formally define the graphical constructs of GOQL.