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.
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.
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.
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.
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.