Recently, I helped a client migrate their legacy desktop application to a web based app.
One of the tools I used was ERD. Here is a sample of the ERD view of an unfinished Rails app I am working on:
I also tested this on my Discourse dev setup (macOS), and it was buggy, but I did manage to get some results (needs work for sure).
This was fairly easy to setup on macOS:
Install GraphViz
$ brew install graphviz
Add these Ruby Gems to your Gemfile
gem 'erd'
gem 'ruby-graphviz'
Install
$ bundle install
(... or whatever you use to get your Gems working).
ERD is not "perfect" and seems to work best on smaller projects; but I don't have enough experience with it yet to say for sure.
There is both an erd and a rails-erd gem. I tried both today, but was able to get the erd Gem below up and running faster. Later I will try rails-erd for fun.
Reference:
See also: