1) It was correct to replace the has_one with belongs_to, as the histories table holds the foreign key, and not the status table. in a has_one or has_many association, AR looks up the primary key in the assiociated table, not in its own.
2) the second association is - if you think about it - also not a has_many relationship, because here the histories tabel also contains the foreign key. So each item in the history table can only be assosiated to one entry of the params table, because each item in "histories" can only have von job_id. or do i get something wrong? Anyways, as it appears to me, this is a belongs_to association, like the first one. give it a try.
