Saylor Academy

Unit 4: The Entity Relationship Model
Databases often hold a great amount of data. In order to build a database, we need to understand which entities should hold data and identify the connections that may exist between entities. In this unit, we will learn about the Entity-Relationship model, which will allow us to create a graphical view of the different elements of a database as well as the relationships between them. We will also learn the drawing conventions of the E-R model using a part-to-whole approach, beginning with those conventions used to represent a single entity, and concluding with conventions used to represent all relations in a database.

Completing this unit should take you approximately 9 hours.
- Unit 4 Learning Outcomes Page
- 4.1: Why Use an E-R Model
  - Indian Institute of Technology, Bangalore: S. Srinath's "Conceptual Designs" Page
    Watch this lecture.
  - Gordon Russell's "Database Analysis"
    Read this chapter, stopping at the "Degree of a Relationship" section.
  - Gordon Russell's "Quiz on ER Diagrams"
    Answer all of the questions in this quiz.
- 4.2: Elements in the Model and Respective Symbols
  - Gordon Russell's "Database Analysis"
    Read this chapter from "Degree of a Relationship" through "Entity Sets".
  - RelationalDBDesign: "Primary Keys” n>
    Read this page.
  - RelationalDBDesign: "Database Foreign Keys"
    Read this page.
- 4.3: The Enhanced ER Model
  - Loren K. Rhodes' "Enhanced Entity-Relationship Model" URL
    Read this page.

CS403: Introduction to Modern Database Systems

Unit 4: The Entity Relationship Model

4.1: Why Use an E-R Model

4.2: Elements in the Model and Respective Symbols

4.3: The Enhanced ER Model