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Introduction

This section of the website provides lecture materials, exercises and videos for Information Systems instructors interested in developing courses for teaching ER Diagrams.

There are a number of ER diagram notations, not all of which are compatible with each other. I cover ER diagrams at a much deeper level than most other instructors. As a result, I employ the box-and-diamond notation rather than crow's foot. There are other syntactic conventions I adopt, mainly because they facilitate communication of semantics better than other notations.

A video explaining the specific choices I have made is here.


The drawing tool I use in the course is Dia. This is an open source tool used to draw a wide range of design diagrams. It is relatively easy to use, and doesn't carry a lot of incorrect assumptions like forcing binary relationship sets which other tools have.

The current contents related to ER diagrams are:

Any questions or comments should be directed to: The creator's email

Basic ER Notation

This video introduces the basic syntax of the box and diamond notation. Box and diamond has harder syntax to understand than the most popular notation- Crow's Foot, but it expresses much deeper semantics than Crow's Foot can.


The exercise described in the video can be found here.

Any questions or comments should be directed to: The creator's email

What a (1,1) on a Relationship Set Means

ER diagrams are fundamentally a way of representing databases at the conceptual level. This means there are equivalent concepts to functional and multivalue dependencies in ER diagrams. This video explains the implications for ER diagrams of the (1,1), the equivalent to the functional dependency.


The exercise described in the video can be found here.

Any questions or comments should be directed to: The creator's email

Sharing Keys, Weak Entity Sets and Subclassing

Here, we explore the idea of two entity sets where the primary key of one entity set is a subset of the primary key of another. There are implications to this kind of relationship.


The exercise described in the video can be found here.

Any questions or comments should be directed to: The creator's email

Unusual ER Diagrams

Many students think relationship sets only connect two different entity sets. We show here that two entity sets can share multiple relationship sets, and relationship sets can have one or more entity sets.


The exercise described in the video can be found here.

Any questions or comments should be directed to: The creator's email

Common Student Mistakes

These are the common errors students make when drawing ER diagrams.


Any questions or comments should be directed to: The creator's email

Structural Errors in ER Diagrams

We discuss four kinds of structural errors here: fan traps, chasm traps, unnecessary cycles and problems with associations.


Any questions or comments should be directed to: The creator's email

ER Diagram Exercises

These are just some ER diagram exercises

An ER Diagram Exercise


The exercise described in the video can be found here.

Another ER Diagram Exercise


The exercise described in the video can be found here.

Any questions or comments should be directed to: The creator's email