title: Does Active Record have has_and_belongs_to_one association?
body: <p>I have a <code>Staff</code> table and a <code>Store</code> table, but each store has up to one manager, and each staff can manage up to one store.</p>
  
  <p>To avoid <a href="https://en.wikipedia.org/wiki/Fourth_normal_form" rel="nofollow">multivalued dependency</a> in 4NF. I want to create a <code>StoreManager</code> table in contrast to another <code>StoreStaffs</code> table which stores information about staffs and the store they work in.. </p>
  
  <p>Nevertheless, <code>Store</code> and <code>Staff</code> has a <strong>one-to-one</strong> relationship through <code>StoreManager</code> table.</p>
  
  <p>Although Rails has <code>has_and_belongs_to_many</code> association, in my case, it will not apply but <code>has_and_belongs_to_one</code> is needed instead.</p>
  
  <p>So is there a possible relationship similar to <code>has_and_belongs_to_one</code> in Rails' Active Record?</p>