Uniqueness_of on many columns

Rails
1

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.

2

Tom A. <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.

3

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.

4

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