# Non-ruby-conform association question **URL:** \ **Category:** Rails\ **Created:** [April 5, 2007, 1:21pm UTC](https://www.ruby-forum.com/t/non-ruby-conform-association-question/91186 "2007-04-05T13:21:33Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![caefer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e36b37/32.png) [@caefer](https://www.ruby-forum.com/u/caefer)\ **Post date:** [April 5, 2007, 1:21pm UTC](https://www.ruby-forum.com/t/non-ruby-conform-association-question/91186/1 "2007-04-05T13:21:33Z")
Hi Folks, I have three tables: history hist\_id =\> Primary Key job\_id status\_id status\_time result\_id status status\_id =\> Primary Key status\_name params job\_id param\_name param\_value History contain something like this: hist\_id job\_id result\_id status\_id status\_time 121 cd2e85b0-c584-0129-0370-0016350d87a7 10600303 7 2007-04-05 11:20:26.0 120 cd2e85b0-c584-0129-0370-0016350d87a7 4 2007-04-05 11:20:23.0 119 cd2e85b0-c584-0129-0370-0016350d87a7 1 2007-04-05 11:20:22.0 Status contents look like this: status\_id status\_name 7 FINISHED 6 CANCELLED 5 FAILED 4 PROCESSING 3 WAITING 2 STARTED 1 INITIALIZED And Params contains lots entries like this: job\_id name value cd2e85b0-c584-0129-0370-0016350d87a7 param\_1 “value 1” cd2e85b0-c584-0129-0370-0016350d87a7 param\_2 “value 2” cd2e85b0-c584-0129-0370-0016350d87a7 param\_3 NULL cd2e85b0-c584-0129-0370-0016350d87a7 param\_4 NULL cd2e85b0-c584-0129-0370-0016350d87a7 param\_5 NULL cd2e85b0-c584-0129-0370-0016350d87a7 param\_6 “value 3” cd2e85b0-c584-0129-0370-0016350d87a7 param\_7 “value 4” cd2e85b0-c584-0129-0370-0016350d87a7 param\_8 NULL cd2e85b0-c584-0129-0370-0016350d87a7 param\_9 NULL […] What I need to do for display/scaffoldingis is this: From History view I want to display the status\_name instead of the status\_id From History view I need to access one or more of the params assigned to the job\_id My first approach went wrong: In history.rb I added set\_primary\_key “hist\_id” has\_one :status, :foreign\_key =\> “status\_id” has\_many :params, :foreign\_key =\> “job\_id” And ActiveRecord tries to execute this SELECT \* FROM PARAMS WHERE (PARAMS.job\_id = ‘121’) or SELECT \* FROM STATUS WHERE (STATUS.status\_id = ‘121’) As you can see in the History table the value for primary key “hist\_id” is “121”. So it looks like ActiveRecord tries to compare apples and oranges. For the status association I could help my self by replacing the has\_one to a belongs\_to relation. This sounds somehow wrong because a history has\_a/has\_one status for each entry. The params relationship only works, when I use set\_primary\_key “job\_id” in history.rb which leads to other bad problems because job\_id is not unique as you can see. To me it looks just like ActiveRecord is too unflexible to handle custom mappings. I would expect ActiveRecord to use something like a local\_key setting to tell that the foreign\_key does not map to the local primary\_key. Am I wrong with my approach? Maybe I have to handle my associations totally diferent. Thanks for any suggestions! Regards, Christian ---
**Author:** ![caefer](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/e36b37/32.png) [@caefer](https://www.ruby-forum.com/u/caefer)\ **Post date:** [April 5, 2007, 1:48pm UTC](https://www.ruby-forum.com/t/non-ruby-conform-association-question/91186/2 "2007-04-05T13:48:08Z")
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. On 5 Apr., 13:21, Christian S. \