CODEWITHSUNDEEP
ruby-on-railsactiverecordrails-activerecord
stonep
stonep

Reputation: 309

Validating uniqueness on two attributes

I have a model named "Cars"

I wonder how I can declare in the model, so that only one record can exist when two attributes match each other. For example, in the Car Model

:owner_id, :driver_id

Let's say a record exists:

:id => "1", :owner_id => "22", :driver_id => "23", :state => "parked"

If I try to create another record, that also had the same owner_id and driver_id that matched each other, the record would not be able to create itself. I am trying to make a relation model that will create one record for each owner and driver, when they are matched.

Upvotes: 1

Views: 1349

Answers (1)

nzifnab
nzifnab

Reputation: 16092

In your Car model you can define a validation:

validates :driver_id, uniqueness: { scope: :owner_id }

I believe this should give you the intended behavior, there will be a validation error if you try creating another car with the same driver and owner.

Upvotes: 8

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