TRANSFORMING EXTENDED ENTITY-RELATIONSHIP MODEL INTO OWL ONTOLOGY IN TEMPORAL DATABASES

Many previous systems were built based on the ER model, so the upgrading and transforming the ER model into ontology for reducing cost is really necessary. There are several studies aim at transforming from ER and EER model into ontology. However, these studies have not classified the semantic of the recursive relationship in ER model, so the semantic of the recursive relationship will be easily lost during the transformation. Also, the studies have not mentioned the designing of the ontology that supports temporal attributes based on the temporal ER model. This paper discusses the semantic classification of the recursive relationship and TimeER model (extended EER in temporal databases) and OWL ontology. And propose a method to transform into OWL ontology

Users' Comprehension of Ternary Relationships in Extended Entity Relationship Model and Object Modeling Technique

This article describes a comparative study on users' understanding of ternary relationships in two kinds of conceptual data modeling techniques: extended entity relationship model (EER) and object modeling technique (OMT). Through literature review, the author realized that there were very few studies that focused specifically on ternary relationships in conceptual data modeling, let alone on users' understanding of ternary relationships. The author conducted an online study on users' understanding of ternary relationships in EER and OMT mdoels with the hypothesis that there was no difference between these two models for users' comprehension of ternary relationships. The result indicates that there is a significant difference in users' understanding of ternary relatinoships in EER and OMT models. Users understand ternary relationships better in OMT model than in EER model

The Effect of Abstraction of Constructs in Data Models on Modeling Performance: An Exploratory Empirical Study

Several data models exist at the conceptual level, the most popular being the Extended Entity Relationship Model (EERM). However, the EERM may be difficult to use by end-users, when specifying their data requirements, and is typically used by systems analysts as a precursor to mapping the data to the relational model, in normalized form. A possible reason why the EERM may be difficult to use by end-users or novice data modelers is that the constructs in the EERM may be abstract with regards to the actual usage of the data. In this research in progress, we present an exploratory empirical study that investigates the effects of abstraction of concepts on novice analysts’ data modeling performance

On Integrity Constraints for a Waste Management Information System

There is a waste problem in nearly every country. A model of a waste generating system and an efficient waste management information system are the first steps to control this problem. Some countries have already enacted laws which force communities and enterprises to report annually the amounts of wastes produced. For example, the German federal state, Lower Saxony, enacted such a law in 1992. This YSSP-Project deals with a case study on the development of a waste management information system for this state. The quality of the system essentially depends on the consistency of the underlying database system. Therefore, the point of view of a database designer is given. The design of the data structures and the support of integrity constraints in the underlying database system is thereby especially emphasized. The data structures are modelled using an extended entity relationship model. They are implemented with a relational database management system. In contrast to the traditional way of supporting integrity constraints in the application program, we define triggers which are implemented in the database system itself to enforce main consistency rules. In the final chapter some conclusions about further steps are given

A note on abstraction in software descriptions

In the process of software development, abstraction is usually treated as a mere change of scale. Therefore, the only widely used principle for changing the level of abstraction is a change in quantity, for instance by stepwise refinement. This paper is based on the observation that there are in fact more differences between descriptions at different levels. Two consequences are suggested: first, an extended Entity-Relationship-Model, and second, a set of abstraction levels, each related to a specific "filter" through which the system is seen. The paper is prefaced by a remark on terminology and by some information on my background

The StarView intelligent query mechanism

The StarView interface is being developed to facilitate the retrieval of scientific and engineering data produced by the Hubble Space Telescope. While predefined screens in the interface can be used to specify many common requests, ad hoc requests require a dynamic query formulation capability. Unfortunately, logical level knowledge is too sparse to support this capability. In particular, essential formulation knowledge is lost when the domain of interest is mapped to a set of database relation schemas. Thus, a system known as QUICK has been developed that uses conceptual design knowledge to facilitate query formulation. By heuristically determining strongly associated objects at the conceptual level, QUICK is able to formulate semantically reasonable queries in response to high-level requests that specify only attributes of interest. Moreover, by exploiting constraint knowledge in the conceptual design, QUICK assures that queries are formulated quickly and will execute efficiently