Abstract not found

. The first goal of the paper is to explicate the formal logic underlying ERdiagrams, ERD-logic. It is shown that this logic is a logic of predicates over set-andfunction diagrams, that is, a graph-based logic. Main principles of graph-based logics are developed, in particular, a principal distinction between a logical specification as such and its visual presentation is carefully drawn and demonstrated in a number of examples. The approach is based on a generalization of the sketch logic developed in the mathematical category theory, our version was designed to adapt the idea for conceptual modeling. Following category theory, specifications of the language we propose are also called sketches, and so the ERD-logic is manifested as the sketch logic. The second goal of the paper is to demonstrate that the problem of semantic models heterogeneity can be naturally managed in the sketch framework. It is shown that data specifications in many of conventional semantic models can be consider...

We introduce MD-sketches, which are a particular kind of Finite Sum sketches. Two interesting results about MD-sketches are proved. First, we show that, given two MD-sketches, it is algorithmically decidable whether their model categories are equivalent. Next we show that data-specifications, as used in database-design and software engineering, can be translated to MD-sketches. As a corollary, we obtain that equivalence of data-specifications is decidable.

. A graph-based specification language and the corresponding machinery are described as stating a basic framework for semantic modeling and database design. It is shown that a few challenging theoretical questions in the area, and some of hot practical problems as well, can be successfully approached in the framework. The machinery has its origin in the classical sketches invented by Ehresmann and is close to their generalization recently proposed by Makkai. There are two essential distinctions from Makkai's sketches. One consists in a different -- more direct -- formalization of sketches that categorists (and database designers) usually draw. The second distinction is more fundamental and consists in introducing operational sketches specifying complex diagram operations over ordinary (predicate) sketches, correspondingly, models of operational sketches are diagram algebras. Together with the notion of parsing operational sketches, this is the main mathematical contribution of the pape...