Trevor H. Jones

Analysis of binary/ternary cardinality combinations in entity-relationship modeling

In this paper, we discuss the simultaneous existence, and relationships, between binary and ternary relationships in entity-relationship (ER) modeling. We define the various interpretations that can be applied to the simultaneous existence of ternary and binary relationships having the same participating entities. We have identified that only certain cardinalities are permitted to exist simultaneously in such ER structures. We demonstrate which binary relationship cardinalities are permitted within ternary relationships, during ER modeling. We develop an Imp licit Binary Cardinality (IBC) rule, which states that, in any ternary relationship, the cardinality of any binary relationship embedded in the ternary, is many-to-many when there are no explicit constraints on the data instances. We then present an Explicit Binary Permission (EBP) rule, which explains and enumerates all permitted binary relationships for various cardinalities of ternary relationships. Finally we present an Implicit Binary Override (IBO) rule, which states that the implicit binary cardinalities can be constrained in a ternary relationship by an explicitly imposed binary relationship. We then use these rules to consider the further implicit dynamics of ternary relationships when multiple binary relationships are imposed. In discussing these findings, we consider the rules in the context of supporting functional dependency analysis. The relevance of the findings is presented in the context of ensuring that all functional dependencies associated with ternary relationships are correctly applied and identifying the potential for decomposing the ternary relationship into multiple binary relationships based on all explicit functional dependencies.

Research Framework and Dimensions for Evaluating the Effectiveness of Educational Technology Systems in Learning Outcomes.

AbstractWhat is the most appropriate technology to use? In what educational context is a particular technology most effective? How effective is the chosen technology? The answers to these questions and others are critical in establishing the value added to the student’s learning and achievement with the use of educational technology. However, these questions are rarely addressed. And, if they are, the results are often unclear, because of the lack of a clear evaluation framework. In this article, we will present and briefly describe a general framework for evaluating the effectiveness of educational technology in enhancing student learning and achievement.

Binary equivalents of ternary relationships in entity-relationship modeling: a logical decomposition approach

Little work has been completed which addresses the logical composition and use of ternary relationships in entity -relationship modeling. Many modeling notations and most CASE tools do not allow for ternary relationships. Alternative methods and substitutes for ternary relationship structures do not necessarily reflect the original logic, semantics or constraints of a given situation. Furthermore, it has been shown that ternary relationships can be constrained by additional implicit binary constraints which do not occur in the logic of binary relationships. This paper develops an analytical perspective of ternary relationships. We investigate the logical relationships implicit to the ternary structure and then identify potential simplification through decomposition into binary equivalents. These alternative binary equivalents allow retention of the implicit logical structure, and consequently also retain the semantics of the original structure. The analysis investigates equivalency of lossless decompositions, preservation of functional dependencies and finally the ability to preserve update constraints (insertions and deletions). We identify which ternary relationships have true, fully equivalent, b inary equivalents and those which do not. We provide an exhaustive analysis of cardinality combinations found in ternary relationships which practitioners can use to guide the way in which they deal with ternary relationships in conceptual modeling.

Binary Representations of Ternary Relationships in ER Conceptual Modelling

Our paper seeks to provide an analysis of ternary relationship logic with an objective of identifying whether they can be decomposed given only the constructs and constraints provided during conceptual entity relationship (ER) modeling.

Ternary relationship decomposition and higher normal form structures derived from entity relationship conceptual modeling

Our paper looks at the potential decomposition of ternary relationships in ER modeling. We suggest that the decomposition of ternary relationships is not provided for by traditional normalization theory which does not consider the specific and implicit semantics of these structures. We provide an analysis which identifies the lossless, functional dependency preserving equivalency between ternary relationships and subsequent binary decompositions. This demonstration of equivalency is based on notation, constructs and semantic requirements which are available at the entity relationship modeling level. We provide a template showing all allowable combinations of ternary/binary cardinalities, and which of those can be losslessly decomposed while preserving functional dependencies. Because of the nature of ternary relationships and the implicit involvement of composite keys, comparisons are often made to the higher normal forms. We discuss the obvious similarities between the decomposition of ternary relationships presented in this paper and the traditional theory behind 4NF and 5NF decompositions. We show that from an entity relationship modeling perspective, it is impractical and inappropriate to consider ternary relationship decomposition under the umbrella of higher normal form decomposition. We suggest that although the theory of the higher normal forms is sound, it has limited practical application when considering ternary relationships. We also discuss the relevancy of this work with regard to their representation in CASE tools, and the inability of binary modeling to logically represent certain ternary relationship cardinalities.

An OO Approach to Designing Business Intelligence Systems

While standard accounting needs tend to be relatively static, the demand for corporate managers to be constantly aware of changing business dynamics is ever present. Consequently, support systems, technical or otherwise, must be up to the challenge of responding to the demands of their users by incorporating available accounting data. This chapter explains how organizations can use object-oriented analysis and design techniques to more effectively create systems to respond to escalating business intelligence needs. Towards this end, we discuss the differences between business intelligence systems and operational accounting systems. We explain basic object-oriented software principles and how data and procedures are viewed within the object-oriented paradigm. We demonstrate how object-oriented systems can evolve more quickly in response to changing business intelligence needs than systems developed using more traditional (structured) methods. Finally, we provide an example demonstrating the application of these principles. The example demonstrates how the collection of retail sales data and the separate recording of advertising expenditures can be combined to address specific business intelligence questions. This allows us to demonstrate how data collected for specific accounting purposes can be rapidly manipulated and combined, to be used in a decision support, as opposed to the regulatory reporting, role.