Postgresql::Check

This gem introduces a few methods to your migrations for adding and removing Check Constraints. It also dumps these constraints to schema.rb.

Requirements

Add this line to your application's Gemfile:

gem 'postgresql-check'

And then execute:

$ bundle

Or install it yourself as:

$ gem install postgresql-check

Two new methods are introduced to migrations:

Given the following model:

class Product < ActiveRecord::Base
  validates :price, :numericality => {:greater_than => 0}
end

You can add a check constraint in your migration:

add_check :products, 'price > 0', :name => 'products_price_check'

The code above generates following SQL:

ALTER TABLE "products" ADD CONSTRAINT "products_price_check" (price > 0)

NOTE: :name option is mandatory now.

To remove constraint use remove_check method:

remove_check :products, :name => 'products_price_check'

This gem adds extra methods to create_table and change_table:

create_table :products do |t|
  t.decimal :price, :null => false
  t.check 'price > 0', :name => 'products_price_check'
end

Remove a check constraint:

change_table :products do |t|
  t.remove_check :name => 'products_price_check'
end