June 22, 2008
June 22, 2008
June 25, 2008
13.1194.1 - 13.1194.9
Temporal Extensions for Enhanced Entity Relationship Notation
Abstract An organization can have many business rules to implement in their daily operations. When these rules deal with the planning of business operations, there can be a strong need to specify the temporal relationships between business objects. Software engineers are seldom educated as to the use of temporal logic though it is often needed to accurately explain time-based relationships. Temporal logic, defines a basic set of primitive relationships that can exist between intervals in time. These same primitive relationships can be used to express temporal relationships between business objects. The Enhanced Entity Relationship (EER) notation allows business rules to be shown in a graphic form using action assertions which keep the business rule at a conceptual level without specifying how the rule will be implemented. In this paper we will show how the EER notation can be augmented to allow a software engineer to specify temporal-based business relationships in a relational data model.
Introduction There are three common types of business rules: structural assertions, action assertions and derivations. A structural assertion is concerned with statements that express an aspect or relationship about the structure of a business. A derivation is concerned with statements that can be used to derive additional information about the business, whereas an action assertion is a statement that controls or limits the actions of the business. Action assertions are important as they define constraints that a business should or must operate under. A business often has many operating constraints that will be implemented in various users’ application programs. Capturing and documenting business rules in an application program can lead to consistency and manageability issues that ultimately leave the database in an inconsistent state.
A more modern and more reliable approach is to define the business constraints (action assertions) at a conceptual level without specifying how the rules will be implemented. The Enhanced Entity Relationship (EER) notation has been used to specify business rules. The EER notation was invented to allow more business rules to be shown in graphical form than the simpler ER notation. Associating business rules with the data that it applies to can be very natural, as the rules are all about the data.
While business constraints come in many different forms, an important type of constraint on a business is a timing-based or temporal constraint. As an introduction to temporal constraints, let us review a problem that has been expressed in EER notation and explore how it could potentially be augmented with temporal constraints. We will skip any formal definition at this time and simply try to present an intuitive introduction to temporal constraints.
Welborn, C., & Sanati-Mehrizy, R. (2008, June), Temporal Extensions For Enhanced Entity Relationship Notation Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. 10.18260/1-2--3580
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