paranoia_null_unique.rb

#!/usr/bin/env ruby

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'pg'
end

conn = PG.connect( dbname: 'paranoia_null_unique' )

conn.exec('
  CREATE TABLE IF NOT EXISTS testing (
    token varchar(32) NOT NULL,
    deleted_at timestamp,
    UNIQUE(token, deleted_at)
  )
')
conn.exec('DELETE FROM testing')

5.times { conn.exec("INSERT INTO testing (token) VALUES ('should_be_unique')") }

conn.exec('SELECT COUNT(*) FROM testing') do |result|
  print "#{result.values.first.first} records!\n"
end