Database Management Systems - Prof. Holowczak

Zicklin School of Business - Baruch College
City University of New York

Database Management Systems

Entity Relationship Modeling

What You'll Learn This Week

Elmasri/Navathe (3rd) ed. Kroenke (7th ed.) McFadden (5th ed.)
Chapter 3 and 4 Chapters 3 Chapters 3 and 4

Entity Relationship Modeling

E-R Modeling Constructs

E-R Diagrams

Variation One - What the Kroenke book uses

[Kronke Book Example ER Diagram]

For this diagram:

These are admittedly clumsy, but you get the point.

Variation Two - Elmasri/Navathe Book

Variation Three - Oracle Designer/2000 CASE

[Oracle CASE Example ER Diagram]

There are a set of tools that can print these "relationship sentences".

Variation Four - Visible Analyst

Variation Five - Sybase PowerDesigner


This is not an Entity Relationship Diagram!

It is true: The "Relationships" screen in MS Access is NOT an Entity Relationship diagramming tool. This is a "physical" level diagram of how the tables are actually created.

Displaying Attributes

[Attributes Example ER Diagram]

[Attributes inside Entity boxes Example ER Diagram]

Weak Entities

Subtype Entities

For Next Week

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File: week3.html Date: Wed Jan 24 10:21:06 EST 2001
All materials Copyright, 1997-2001 Richard Holowczak