uniqueness_of on many columns

Greetings!

I’m trying to set up a validation to ensure that a record is unique across three columns; col_one, col_two, col_three.

tried this:
validates_uniqueness_of :col_one, :scope=>[:col_two, :col_three]

and it really doesn’t work at all like I had hoped.
the docs says this should work

    class TeacherSchedule < ActiveRecord::Base
validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
end

Just want to know if there are any experiences out there to share before I write my own validation code.

Tom Allison <tom@...> writes:

Greetings!I'm trying to set up a validation to ensure that a record is

unique across three columns; col_one, col_two, col_three. tried
this:validates_uniqueness_of :col_one, :scope=>[:col_two, :col_three]and it
really doesn't work at all like I had hoped.the docs says this should work
class TeacherSchedule < ActiveRecord::Base

    validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
  end
Just want to know if there are any experiences out there to share before I

write my own validation code.

Composite keys are frowned upon. You might want to reconsider what you are
attempting and introduce a few models to handle the relationship.

Of course, you could always create a customer validator. See the rails API.

Yeah, but in this case I’m just regurgitation someone else’s data and I don’t want to pick up duplicate records.

Can you post your sample data here and if possible your model and controller code?

I have used it on several apps, and works just fine for me.