README.md
# Postgresql::Check
[](https://codeclimate.com/github/take-five/postgresql-check)
This gem introduces a few methods to your migrations for adding and removing
[Check Constraints](http://www.postgresql.org/docs/9.3/static/ddl-constraints.html).
It also dumps these constraints to `schema.rb`.
## Requirements
* PostgreSQL
* active_record >= 3.2.0
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'postgresql-check'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install postgresql-check
## Usage
Two new methods are introduced to migrations:
* `add_check table_name, condition, name: constraint_name`
* `remove_check table_name, name: constraint_name`
Given the following model:
```ruby
class Product < ActiveRecord::Base
validates :price, numericality: { greater_than: 0 }
end
```
You can add a check constraint in your migration:
```ruby
add_check :products, 'price > 0', name: 'products_price_check'
```
The code above generates following SQL:
```sql
ALTER TABLE "products" ADD CONSTRAINT "products_price_check" (price > 0)
```
**NOTE**: `:name` option is mandatory now.
To remove constraint use `remove_check` method:
```ruby
remove_check :products, name: 'products_price_check'
```
## Change Table methods
This gem adds extra methods to `create_table` and `change_table`:
```ruby
create_table :products do |t|
t.decimal :price, null: false
t.check 'price > 0', name: 'products_price_check'
end
```
Remove a check constraint:
```ruby
change_table :products do |t|
t.remove_check name: 'products_price_check'
end
```
## Future plans
* Write tests
* Auto-generate constraint name
* Make `remove_check` reversible
## Contributing
1. Fork it ( https://github.com/take-five/postgresql-check/fork )
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request