Developing High Quality Data Models

5. Some Observations on Data Models and Data Modeling

Chapter Outline

5.1 Limitations of Data Models 51

5.1.1 One Entity Type Cannot Be Shown as Having Another as an Instance 51

5.1.2 An Entity Type Cannot Be Shown as Having an Instance of Any Entity Type as a Subtype 53

5.1.3 Understanding the Limitations 54

5.1.4 Data Model vs. Reference Data 54

5.2 Challenges in Data Modeling 55

5.2.1 Key Requirements for Information Systems 55

5.2.2 The Reality of Computer-Based Information 56

5.2.3 The Role of Data Models 57

5.2.4 Desiderata 58

5.2.5 Some Key Issues for Data Models 59

5.1. Limitations of Data Models

Entity relationship models are limited in what they can express. It helps to be ...