I'm doing something I hope will be of value to the Joomla community, whether you're working on the core, plugins, or you are a site developer. My contribution is a Joomla Entity Relationship Diagram (ERD).
I've reversed the Joomla 1.0 database into an ERD tool. Unfortunately it can't infer relationships, so I'm going through putting those back together, and documenting the ERD. The diagrams use IE notation.
I like to include data from any "lookup" tables, as well as sample data, whenever it really seems to help explain what the table is designed to do. I'm also including notes about things I am unsure of.
I am breaking this up into subject area pieces. I may be able to provide a complete diagram once I'm finished, but I also find it beneficial to have smaller subject areas.
First off, please understand I'm relatively new to Joomla. If I'm getting anything wrong, don't hesitate to let me know.
When the diagram is complete I'll look at rendering it to a pdf to make it easier for people to print.
I hope these diagrams will be useful to the Joomla community now and in the future.
We're in the process of integrating this into the developers manual. I've created a single pdf with all the views, which prints out nicely on 8.5x11 paper. Until the file is available from the manual, you can get it here: Combined ERD