I have a one to many association between jobs and companies and it works fine. In the job form view I have text_field for the company name with an autocomplete feature. The auto
Company.find_or_create_by(name: name)
It should work out of the box. Only thing that can prevent it from creating record is validation errors.
Try this in rails console
to check if its working or not.
And check the validation errors as well.
name = "YOUR TEXT FOR NAME ATTRIBUTE"
c = Company.find_or_create_by(name: name)
puts c.errors.full_messages