COMIC: A System for Conceptual Modelling and Information Construction

The designer of a data base or an information system has to develop conceptual models describing the Universe ofDiscourse (UoD) for the specification of meaning and semantic structure of the data. He has also to handle descriptions ofdata structures and perform technical design of the system. Finally the system must be implemented. Often the amount of work required is so large that it would be useful to have a computerized tool to support the design process. In this paper such an integrated system is briefly described. The system, called COMIC, supports first the conceptual modelling phase, then the logical design phase, and finally the implementation of the data base, and moreover it can be used as a query and update system of the data base. The graphical language, CONCEPT D, used to describe a conceptul schema is new. CONCEPT D is a visual language that supports conceptual modelling of the DoD, the development of a conceptual schema, and the use of the application data base corresponding to the conceptual schema. The language is based on the intensional approach to conceptual modelling, i.e. the descliption of knowledge in concepts is emphasized instead of extensions of these concepts. The language contains three sub-languages: one, called CONCEPT DID, for knowledge acquisition about concepts used in the DoD and developing graphic descriptions of concept definition hierarchies, one, called CONCEPT DICS, for describing conceptual schemata of the UoD, and one, called Conceptual Query Language CQL, for interacting with the application data base. A conceptual schema is used as a basis for making queries from the application data base corresponding to the conceptual schema. A graphic conceptual schema supports the user in recalling and understanding the conceptual structure of the DoD. It hides the relational data base schema from the user so that he works only with concepts of the UoD. Hehasnot to know e.g. therelations or foreign keys between relations. In this work someofthemain features ofCQL are presented. A query is formulated by pointing at concepts required, and possibly by giving some selection criteria and instructions for formatting the output. CQL is unique in its capability in manipulating concept definition hierarchies. The core component of the COMIC system is the concept data base on which other components, such as a conceptual schema editor, a schema translator and a conceptual query language have been built.