Rails - How to use Find Or Create

Question

I have the following:

@permission = @group.permissions.create(
  :user_id => @user.id,
  :role_id => 2,
  :creator_id => current_user.id)

How can I update that to be find_or_create, so that if this record already exists, it's assigned to @permission, and if it doesn't exist, the record is created?

Answer 1

While the accepted answer is correct it's important to note that in Rails 4 this syntax will be changing (and the hash syntax). You should be writing the following:

@permission = Permission.where(
  user_id: @user.id, 
  role_id: 2, 
  creator_id: current_user.id).first_or_create

Which actually looks much closer to your original method! See the sub-section Deprecated Finders for more details.

Answer 2

Related topic:

find_or_create_by in Rails 3 and updating for creating records

You can extend ActiveRecord with your own update_or_create method (see related topic) and then you can use this

@permission = Permission.update_or_create_by_user_id_and_role_id_and_creator_id(@user.id, 2, current_user.id) do |p|
  p.group_id = @group.id
end

Or you can use find_or_create_by... method:

@permission = Permission.find_or_create_by_user_id_and_role_id_and_creator_id(@user.id, 2, current_user.id)
@permission.group = @group
@permission.save