erbwiz

Generate Entity-Relationship Diagrams from text

Preparing System

On MacOS

$ brew install wget graphviz

On Ubuntu

# sudo apt-get install graphviz

Both

$ wget https://github.com/weapp/erbwiz/raw/master/erbwiz.rb
$ chmod +x erbwiz.rb

Generating images

$ ./erbwiz.rb inputs.er output.pdf

Options:

The default notation is ie, but we can change to uml:

$ ./erbwiz.rb -n uml inputs.er output.pdf

Example:

# Tables
[User] { color: :blue }
*id
blog_id* <nullable>
name

[Blog] { color: :orange }
*id
user_id*
title
logo <url>

[Post]
*id
blog_id*
title
body

# Relations
[User] 1--? [Blog]
[Blog] 1--* [Post]
[Post] +--* [Tag]
[Post] 1--* [Comment]
[User] 1--* [Comment]
[User] *--* [User] <friendship>

# Extras
[Post] == [Comment]