Validate uniqueness of multiple columns

ruby-on-rails ruby-on-rails-3 validation activerecord rails-activerecord
re5et picture re5et · Feb 2, 2011 · Viewed 70.4k times · Source

Is there a rails-way way to validate that an actual record is unique and not just a column? For example, a friendship model / table should not be able to have multiple identical records like:

user_id: 10 | friend_id: 20
user_id: 10 | friend_id: 20

Answer

Dylan Markow picture Dylan Markow · Feb 2, 2011

You can scope a validates_uniqueness_of call as follows. 

validates_uniqueness_of :user_id, :scope => :friend_id

Related questions

Rails - Validate Presence Of Association?

I have a model A that has a "has_many" association to another model B. I have a business requirement that an insert into A requires at least 1 associated record to B. Is there a method I can call to …

Read More
validation custom message for rails 3

Rails has introduced new way to validate attributes inside model. When I use validates :title, :presence => true it works but when I try to add a custom message validates :title, :presence => true,:message => "Story title is required" …

Read More
Ruby on Rails Callback, what is difference between :before_save and :before_create?

Could you explain in detail what the :before_save and :before_create Ruby on Rails callbacks are, and what they have to do with Rails validations? Does validation occur after :before_save or :before_create?

Read More