In this paper, we motivate and present a data model for conceptual design of structural and behavioural aspects of databases. We follow an object centered design paradigm in the spirit of semantic data models. The specification of structural aspects is divided into modelling of object structures and modelling of data types used for describing object properties. The specification of object structures is based on an Extended Entity--Relationship (EER) model. The specification of behavioural aspects is divided into the modelling of admissible database state evolutions by means of temporal integrity constraints and the formulation of database (trans)actions. The central link for integrating these design components is a descriptive logic-- based query language for the EER model. The logic part of this language is the basis for static constraints and descriptive action specifications by means of pre- and postconditions. A temporal extension of this logic is the specification language for tem...

. This paper gives a cohesive approach to modeling and implementation with graphs. This approach uses extended entity relationship #EER# diagrams supplemented with the Z-like constraint language GRAL. Due to the foundation of EER#GRAL on Z a common formal basis exists. EER#GRAL descriptions give conceptual models which can be implemented in a seamless manner by e#cient data structures using the GraLab graph library. Descriptions of four medium size EER#GRAL-applications conclude the paper to demonstrate the usefulness of the approach in practice. 1 Introduction Using graphs as a means for discussing problems, as a medium for formal reasoning, or as a paradigm for data structures in software is folklore in today's computer science literature. But most of the di#erent approaches that use graphs are not used in a coherentway. There are di#erent models in use based on undirected or directed graphs, with or without multiple edges or loops. Sometimes graph elements are typed or at...

We translate Entity-Relationship (ER) schemas into the object-oriented specification language TROLL light . This language describes the Universe of Discourse (UoD) as a system of concurrently existing and interacting objects, i.e., an object community. Thereby two essential aspects, structure and behavior, are integrated in one formalism. By doing the translation from ER to TROLL light we preserve the visual advantages of the former and receive a formalism through the latter which can be mapped to an adequate object-oriented database system. Proceeding this way we hope our proposal for transforming ER schemas into TROLL light specifications provides a valuable link between structural and dynamic modeling. 1 Introduction Proc. 12th Int. Conf. on Entity-Relationship Approach (ER'93) R. Elmasri, V. Kouramajian, B. Thalheim (Eds.), Springer, Berlin, LNCS 823, pp. 376--389 (1994) Nowadays the Entity-Relationship approach [Che76] has been accepted as a quasi standard [Teo90, BCN92] for the ...

. In this paper a conceptually simple structural object model focusing on object types, attributes and ISA relationships is introduced. The model is derived mainly from an extended Entity-Relationship approach, but concepts from other semantic and object-oriented models have influenced its features. It is shown how high-level conceptual data models can be mapped to this model, and to what extent the object model subsumes classical modeling paradigms. 1 Introduction In recent years numerous data models for the conceptual modeling of information systems have been proposed. Among them there are semantic data models like SDM [13], IFO [3] and (extended) ER models [8, 9, 10, 24, 31, 34], complex object models like [1, 18, 26], purely object-based models like FDM [28] as well as object-based models with complex values such as [22]. All the approaches have different motivation, terminology, and aims. Here we aim to show you how some of these models can be translated into a conceptually simpl...

We present the hybrid query language HQL/EER for an Extended Entity-Relationship model. As its main characteristic, this language allows a user to use both graphical and textual elements in the formulation of one and the same query. We demonstrate the lookand -feel of this query language by means of examples, and show how syntax and semantics of this language are formally defined using programmed graph rewriting systems. Although we present the language in the context of the EER model, the concept of hybrid languages is applicable in the context of other database models as well. We illustrate this claim by discussing a prototype implementation of a Hybrid Query Tool based on an object-oriented approach, namely the Object Modeling Technique (OMT). 1 Introduction The database research efforts of the past decade have provided us with a wide range of both database models and systems, allowing the user to perform complex manipulations on data structures of high modeling power. Th...

. In this paper, we describe the specification of communication relationships between objects in a framework for object-oriented conceptual modeling of information systems. In our approach, objects have an observable state and can evolve by the occurrence of events. The possible behavior of objects over time is modeled by a set of admissible object life cycles. A high-level approach to specify systems of interacting objects should provide a means to specify communications between objects explicitly. We introduce language features for the specification of communications and present an approach to transform such relationships into communication channels in order to make implementation easier. 1 Introduction Object-oriented approaches towards conceptual modeling of dynamic object systems have become very popular. We are of the opinion, however, that a pure object-oriented approach (as promoted by the Object-Oriented Programming community [1]) is not suitable in the conceptual modeling ph...

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The combination of logic programming and databases has been given broad attention in recent years. However, mainly the connections between the relational data model and logic programming have been investigated. The application of logic programming languages as a basis for information systems founded on more complex, i.e. conceptual data models has received comparatively less attention. With the system Queer, we introduce the prototype of a Prolog-based information system which directly supports an extended entity-relationship model on its front-end and uses a semantically well-founded query and manipulation language based on an entity-relationship calculus. The system basically consists of a set of compilers written in Prolog which translate data specifications, schema definitions, queries, and data-manipulation statements into Prolog programs.

The system Queer is a prototype of an information system design tool which directly supports an extended Entity-Relationship model on its front-end and uses a semantically well-founded query and manipulation language based on an EntityRelationship calculus. The system basically consists of a set of compilers written in Prolog which translate data specifications, schema definitions, queries, integrity constraints, and data-manipulation statements into Prolog programs. All features mentioned are implemented in form and extent as described here. Keywords: Conceptual Modelling; Entity Relationship Model; Object-Oriented Modelling; Logic Programming; Prototyping. 1 Introduction Conceptual modelling plays the central role among the different steps in database design. The result of the modelling process is a comprehensive and first formal description of the part of the world to be modelled. Usually, this step is done by employing a semantic data model like TAXIS [35], SDM [17], IRIS [32], o...

Due to the interactive nature of the specification task, it is desirable and necessary for a specification environment to support a collection of pre-defined or already verified modules on secondary storage. This possibility also enhances the modularity features of specification languages. The present paper defines a conceptual model for the algebraic specification language ACT ONE and its accompanying specification environment. But the approach chosen is quite general and can be employed for other specification languages as well. The definition of the database schema (including integrity constraints) is done by means of an expressive and semantically well-founded extended entity-relationship model and a respective calculus. The basic idea is to start with the context free grammar of ACT ONE and to introduce entity types for non-terminal symbols. Productions are modelled by a type construction (a peculiarity of the extended entity-relationship model) and appropriate components (entity-...