I have been on a multi-year quest to find a tool that would allow me to easily generate ERDs (entity-relationship diagrams) on the Windows platform. Having tried and been disappointed by a large number of free and paid products, the other day I stumbled on one that is easy to use and is 100% free, called Dia (http://dia-installer.de).
According to the online help…
Dia is an application for creating technical diagrams. Its interface and features are loosely patterned after the Windows program Visio. Features of Dia include multiple-page printing, export to many formats (EPS, SVG, CGM and PNG), and the ability to use custom shapes created by the user as simple XML descriptions. Dia is useful for drawing UML diagrams, network maps, and flowcharts.
One of my favorite things about Dia is how intuitive the interface is. I was able to produce the following in a few minutes without consulting the online help at all.
Note that I’ve chosen “Database” from a drop down menu of diagram types, and as a result, three diagram tools have appeared. I can use the leftmost one to insert tables into the work area.
What’s interesting here is that the four tables represented above aren’t just boxes on a screen. They are “table objects”, and double clicking on them brings up editable properties.
…so, in a nutshell, all you need to do is:
- throw some tables onto the work area
- specify key fields and attributes
- draw lines to connect the tables via the appropriate key fields
…and you’ve built a professional looking ERD.
Hint: set scaling like so under Page Setup if you want your ERD to always fill a single page; otherwise it will likely require multiple pages to print.