Understanding implementations of IS-A Relations

Most information system conceptual models. At the other side of design methodologies, where standard DBMSs are used, and will still be used for several tears, there is no explicit representation of these IS-A relations. As a consequence, all the current methodologies include a step through which these semantic constructs are transformed into standard structures. However, it quiskly appears that the translation rules proposed are most often incomplete, and sometimes incorrect. This fact has been experienced by many practitioners, who are faced with complex translation problems, but who do not find satisfying help neither in modern text book, nor in CASE tools. The aim of this paper is to analyze IS-A relations is some detail, and to propose a wide range of complete and correct techniques to express IS-A relations into standard constructs. The relational implementation is adopted to demonstrate the validity of the approach. Strongly revised version of "Representation of IS-A Relations".