Generating Entity Relationship Diagrams (ERD) with ruby Sequel and Graphiz

dot_to_png.sh

#! /usr/bin/env bash
#
# Usage: ./dot_to_png input.dot output.png

if [ ! -x $(command -v dot) ]
then
  echo 1>&2 "dot missing in \$PATH"
  echo 1>&2 "Couldn't find graphiz"
  exit 2
fi
 
dot -Tpng "$1.dot" > "$2.png"

sequel_schema_dumper.rb

#! /usr/bin/env ruby

require "sequel"
require 'sequel_schema_dot_generator'

DB = Sequel.connect("postgres://user:password@localhost:5432/my_database")

File.open("schema_dump_#{Time.now}.dot", "w+") do |file|
  file.write(
    SequelSchemaDotGenerator::Generator.new(db: DB).generate
  )
end