Although Entity-Relationship (ER) modelling techniques are commonly used for information modelling, Object-Role Modelling (ORM) techniques are becoming increasingly popular, partly because they include detailed design procedures providing guidelines for the modeller. As with the ER approach, a number of different ORM techniques exist. In this paper, we propose an integration of two theoretically well founded ORM techniques: FORM and PSM. Our main focus is on a common terminological framework, and on the notion of subtyping. Subtyping has long been an important feature of semantic approaches to conceptual schema design. It is also the concept in which FORM and PSM differ the most in their formalization. The subtyping issue is discussed from three different viewpoints covering syntactical, identification, and population issues. Finally, a wider comparison of approaches to subtyping is made, which encompasses other ER-based and ORM-based information modelling techniques, and highlights how formal subtype definitions facilitate a comprehensive specification of subtype constraints.

which is available at

Flat graphical, conceptual modeling techniques are widely accepted as visually effective ways in which to specify and communicate the conceptual data requirements of an information system. Conceptual schema diagrams provide modelers with a picture of the salient structures underlying the modeled universe of discourse, in a form that can readily be understood by and communicated to users, programmers and managers. When complexity and size of applications increase, however, the success of these techniques in terms of comprehensibility and communicability deteriorates rapidly.

This paper was presented at OOER'95: 14 th International Conference on Conceptual Modeling, Springer LNCS, vol. 1021, pp. 191-203, and is reproduced here by permission

In this article the Uniquest Algorithm (the "quest for uniqueness"), defined in the Predicator Model, is discussed in depth. The Predicator Model is a general platform for object-role models. The Uniquest Algorithm is a constructive formal definition of the semantics of uniqueness constraints. As such, it facilitates the implementation in so-called CASE-tools. The Uniquest Algorithm provides a systematic approach for the interpretation of complex uniqueness constraints. This interpretation process is easily traced, using an extra formalism, called the Object Relation Network (ORN). The ORN is a directed graph with labelled edges, representing an object-role information structure. Intermediate results that are outside the scope of the information structure at hand, are represented elegantly as an ORN. A number of theoretical and practical examples prove the power of the Uniquest Algorithm. In these examples we will encouter complex uniqueness constraints, that are missed easily. The Un...

In this paper we present EVORM, a data modelling technique for evolving application domains. EVORM is the result of applying a general theory for the evolution of application domains to the object role modelling technique PSM, a generalisation of ER, EER, FORM and NIAM. First the general theory is presented. This theory describes a general approach to the evolution of application domains, abstracting from details of specific modelling techniques. This theory makes a distinction between the underlying information structure and its evolution on the one hand, and the description and semantics of operations on the information structure and its population on the other hand. Main issues within this theory are object typing, type relatedness and identification of objects. After a (short) introduction to PSM, this general theory is applied, resulting in EVORM. Besides having a right of its own, the usefulness of the general theory is demonstrated by interpreting its abstract results,...

The numerous information systems design methods and specification techniques being proposed, can be compared on the basis of different criteria. In this paper a framework for ordering information systems modelling techniques based on meta models is proposed. This framework, called the Meta Model Hierarchy, positions each technique according to an analysis of the distinctions between the basic concepts, and the set of constraints defined on these concepts.

Abstract. Verbalization is the process of writing the semantics captured in axioms into natural language sentences, which enables domain experts (who are not trained to understand technical/formal languages) to be able to participate in the modeling and validation processes of their domain knowledge. We present a novel approach

A number of proposals have been made to extend conventional data modelling techniques with concepts for modelling complex object structures, such as power types, sequence types and schema types. A drawback of the introduction of such new concepts is that the original simplicity of a single populatable concept is lost. In this paper we will show how a new kind of constraint, the extensional uniqueness constraint, can overcome this problem. Another advantage of this constraint is that it enables a less rigid identification schema. The usefulness of this new constraint is demonstrated in some concrete modelling situations. 1 Introduction Nowadays it is commonly accepted that information systems are best specified at the conceptual level first. Usually, two perspectives are distinguished at the conceptual level, the data and the process perspective. Many approaches to conceptual modelling of the data perspective exist. A well established class of conceptual data modelling techniques are t...

In this paper, we introduce a query language for evolving information systems. Evolving information systems go beyond the capacity of conventional database systems, not only as they incorporate a time dimension, but also since they allow all aspects of the system to evolve. The introduced language is related to the philosophy underlying NIAM (Natural language Information Analysis Method). This method investigates the grammar of the communication in the Universe of Discourse. Usually this grammar is depicted as an information structure diagram (NIAM or ER schema). This paper describes the language Elisa-D, which is based on this grammar. As a result, expressions in this language have a direct meaning in the universe of discourse, while natural language expressions are easily formalised in this language. keywords: Evolving Information System, Conceptual Query Language EVORM ER, PSM, Elisa-D 1 Introduction Flexible behaviour of an organisation may entail a rapidly changing info...