Suitable E-R notation for introductory DB design course? Good/free diagram tools?

Question

I've taught a database design course for a few years now, starting off each time using the Crow's Foot diagram notation for our entity-relationship models. I can't believe anyone seriously uses the Chen notation (especially for attributes), and I don't find the IDEF1X relationship symbols intuitive at all, particularly for students new to the concepts of cardinality and participation.

Thanks to tools like ERwin, I'm aware of the popularity of methodologies like IDEF1X, but has anyone found greater success with a different modelling notation in an educational setting?

And while we're at it, does anyone know of a good--preferably free and online--diagramming tool that supports these notations? Gliffy seems to have good support for Crow's Foot, and the free basic edition seems capable for an introductory course. Any others?

Answer 1

Dia is free, and there are enough basic shapes to make E-R notation diagrams, and probably al others you've mentioned, but there are no guides that limit you to making only one type of diagram, which may confuse new users or people who don't know the specific notations. I used it for all my assignments in my database course where the prof asked for E-R diagrams.

Answer 2

Dia is a program I used a while back. There's also a Windows version available. It wasn't perfect, but it did the job. Umbrello can produce ER diagrams aswell.

These pieces of software market themselves more as UML/all-round diagram tools, however, so their ER-specific prestige may vary. But they might still be something worth looking at.

Answer 3

There was a similar question for an app for Linux, but the app is Java based so works on any Java-supporting platform:

SQL Developer: http://sqldeveloper.solyp.com/download/index.html

Answer 4

I had looked at Dia a couple of years ago. It didn't support Crow's Foot at the time (but I don't want to wed myself to that notation anyway). It's certainly not the "prettiest" tool I've laid eyes on, but I suppose I should be focusing on content over form anyway.

SQL Developer does look pretty nifty. It doesn't seem to handle true E-R diagrams though. From what I can see, it's capable of producing what I would call schema, or physical, diagrams, containing RDBMS implementation details like primary and foreign keys. I prefer to leave those out of the design until it's time to translate the conceptual model to a physical one.

Answer 5

I would say Umlet over Dia. It's really minimal, but you can use it as a standalone application or plug-in into eclipse and gets the job done.

Answer 6

Visual Paradigm is quite handy for diagraming, and the community edition is free (not all the features are available in that edition, but the ER diagram part is included).

Answer 7

Hi,

DBSchemaeditor it's crow's feet based, online (Silverlight based) and free.

http://www.dbschemaeditor.com

This tool has options to share diagrams, so a teacher can have access granted to the student's folders and check the progress of their excercises.

HTH Braulio

Answer 8

Having presented data models to users at all levels of the business org chart as well as technical professionals up and down the Zachman Framework, hands down the most intuitive relationship notation has been crow's foot.

So most data modeling tools support a hybrid of IDEF1x notation with the substitution of crow's feet instead of the default IDEF1x notation.

This is sometimes referred to in the tools as "information engineering" or "Martin" notation, although neither is technically correct.

There are affordable tools out there will limited feature sets. I would point educators to the main data modeling tool vendors, though, as many offer affordable education licenses or community editions of their products.

For instance, CA offers a community edition (free) of ERwin Data Modeler and IBM/Telelogic Systems Architect has a long history of education-friendly licensing schemes. I'm guessing that other vendors offer similar licenses.

Answer 9

SchemaCrawler is a free, open source tool that can generate E-R diagrams, with the help of GraphViz. You can use regular expressions to select the tables and columns you want to display. Relationships are inferred from commonly used naming conventions.

Answer 10

You should try Creately - Collaborative Online Diagramming. They have pretty comprehensive support for Crows Foot as well as other notations.

It's free and the usability is exceptionally good.

Answer 11

A web-based database diagram tool that support crow's feet notation: SchemaBank. They have free plans and (I guess) education pricing for heavy-duty commercial plans.