Rails - Mar 2006 - AHHHhhhhh... has_and_belongs_to_many, that is going on?

I don''t have a class by the name of "ReviewersScoreCard", yet
my many to
many configuration looks as follows. And, these errors while running some
simple test with ./script/console is giving me a headache:

./script/console
Loading development environment.
>> r = Reviewer.find_first
=> #<Reviewer:0x19d0a48 @attributes={"id"=>"1",
"first_name"=>"Big",
"last_name"=>"Bird"}>
>> r.candidates
=> [#<Candidate:0x19c6340
@attributes={"status"=>"",
"id"=>"1",
"sponsor"=>"",
"first_name"=>"Jim",
"last_name"=>"Jeffrey",
"reviewer_id"=>"1"}>, #<Candidate:0x19c62c8
@attributes={"status"=>"",
"id"=>"2", "sponsor"=>"",
"first_name"=>"Lam",
"jack"=>"johnson",
"reviewer_id"=>"1"}>]
>> r.reviewers_score_cards
NameError: uninitialized constant ReviewersScoreCard
        from ...dependencies.rb:195:in `const_missing''
        from ...association_proxy.rb:12:in `initialize''
        from ...has_and_belongs_to_many_association.rb:5:in `eval''
        from ...association_proxy.rb:12:in `initialize''
        from ...has_and_belongs_to_many_association.rb:5:in
`initialize''
        from ...associations.rb:753:in `new''
        from ...associations.rb:753:in `reviewers_score_cards''
        from ...associations.rb:749:in `reviewers_score_cards''


Here are my models:

class Reviewer < ActiveRecord::Base
  has_many :candidates
  has_and_belongs_to_many :reviewers_score_cards
end

class ScoreCard < ActiveRecord::Base
  has_and_belongs_to_many :reviewers_score_cards,
    :join_table => "reviewers_score_cards"
end

class Candidate < ActiveRecord::Base
  belongs_to :reviewers
end

What is with the reference to ReviewersScoreCard in the error message?

I did not create the model ReviewerScoreCard, but even if I did
ReviewersScoreCard
is being looked up instead. Shouldn''t the model be ReviewerScoreCard?.
I
even tried creating a model by that name and received the same error. What
am I doing wrong? I have tried all the examples I can find on the web about
many-to-many and they all work. Any help would be greatly appreciated.


Thanks in advance,
_arwuah

Just in case. My DDL looks as follows:

DROP TABLE IF EXISTS reviewers;
CREATE TABLE reviewers (
  id              int unsigned  not null auto_increment,
  first_name      varchar(60)   not null,
  last_name       varchar(60)   not null,
  primary key(id)
);

DROP TABLE IF EXISTS candidates;
CREATE TABLE candidates (
  id              int unsigned  not null auto_increment,
  reviewer_id     int unsigned  not null default 0,
  first_name      varchar(60)   not null,
  last_name       varchar(60)   not null,
  sponsor         varchar(120)  not null,
  status          varchar(30)   not null,
  constraint fk_cr_reviewer foreign key (reviewer_id) references
reviewer(id),
  primary key(id)
);

--
-- Table structure for table `reviewers_score_cards`
--
DROP TABLE IF EXISTS reviewers_score_cards;
CREATE TABLE reviewers_score_cards (
  reviewer_id     int unsigned not null default 0,
  score_card_id   int unsigned not null default 0,
  constraint fk_rsc_reviewer foreign key (reviewer_id) references
reviewer(id),
  constraint fk_rsc_score_card foreign key (score_card_id) references
score_cards(id),
  primary key(reviewer_id, score_card_id)
);

--
-- Table structure for table `score_cards`
--
DROP TABLE IF EXISTS score_cards;
CREATE TABLE score_cards (
  id                                      int unsigned not null
auto_increment,
 appears_calm                            int unsigned not null default 0,
 ...
 primary key(id)

);
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Hey

Arwuah _ wrote:
> I don''t have a class by the name of
"ReviewersScoreCard", yet my many to
> many configuration looks as follows. And, these errors while running 
> some simple test with ./script/console is giving me a headache:
> 
> ./script/console
> Loading development environment.
>  >> r = Reviewer.find_first
> => #<Reviewer:0x19d0a48
@attributes={"id"=>"1",
"first_name"=>"Big",
> "last_name"=>"Bird"}>
>  >> r.candidates
> => [#<Candidate:0x19c6340
@attributes={"status"=>"",
"id"=>"1",
> "sponsor"=>"",
"first_name"=>"Jim",
"last_name"=>"Jeffrey",
> "reviewer_id"=>"1"}>, #<Candidate:0x19c62c8
@attributes={"status"=>"",
> "id"=>"2", "sponsor"=>"",
"first_name"=>"Lam",
"jack"=>"johnson",
> "reviewer_id"=>"1"}>]
>  >> r.reviewers_score_cards
> NameError: uninitialized constant ReviewersScoreCard
>         from ...dependencies.rb:195:in `const_missing''
>         from ...association_proxy.rb:12:in `initialize''
>         from ...has_and_belongs_to_many_association.rb:5:in `eval''
>         from ...association_proxy.rb:12:in `initialize''
>         from ...has_and_belongs_to_many_association.rb:5:in
`initialize''
>         from ...associations.rb:753:in `new''
>         from ...associations.rb:753:in `reviewers_score_cards''
>         from ...associations.rb:749:in `reviewers_score_cards''
> 
> 
> Here are my models:
> 
> class Reviewer < ActiveRecord::Base
>   has_many :candidates
>   has_and_belongs_to_many :reviewers_score_cards
> end
> 
> class ScoreCard < ActiveRecord::Base
>   has_and_belongs_to_many :reviewers_score_cards,
>     :join_table => "reviewers_score_cards"
> end
That should be something like:

class Reviewer < ActiveRecord::Base
   has_many :candidates
   has_and_belongs_to_many :scorecards
end

class ScoreCard < ActiveRecord::Base
   has_and_belongs_to_many :reviewers
end

And if you name your join table reviewers_scorecards (without the second 
underscore) rails should pick it up automatically.

Michael

On Mar 20, 2006, at 6:12 PM, Michael Kaiser wrote:
> Hey
>
> Arwuah _ wrote:
>> I don''t have a class by the name of
"ReviewersScoreCard", yet my
>> many to many configuration looks as follows. And, these errors  
>> while running some simple test with ./script/console is giving me  
>> a headache:
>> ./script/console
>> Loading development environment.
>>  >> r = Reviewer.find_first
>> => #<Reviewer:0x19d0a48
@attributes={"id"=>"1",
>> "first_name"=>"Big",
"last_name"=>"Bird"}>
>>  >> r.candidates
>> => [#<Candidate:0x19c6340
@attributes={"status"=>"",
"id"=>"1",
>> "sponsor"=>"",
"first_name"=>"Jim",
"last_name"=>"Jeffrey",
>> "reviewer_id"=>"1"}>,
#<Candidate:0x19c62c8 @attributes=
>> {"status"=>"", "id"=>"2",
"sponsor"=>"",
"first_name"=>"Lam",
>> "jack"=>"johnson",
"reviewer_id"=>"1"}>]
>>  >> r.reviewers_score_cards
>> NameError: uninitialized constant ReviewersScoreCard
>>         from ...dependencies.rb:195:in `const_missing''
>>         from ...association_proxy.rb:12:in `initialize''
>>         from ...has_and_belongs_to_many_association.rb:5:in
`eval''
>>         from ...association_proxy.rb:12:in `initialize''
>>         from ...has_and_belongs_to_many_association.rb:5:in  
>> `initialize''
>>         from ...associations.rb:753:in `new''
>>         from ...associations.rb:753:in `reviewers_score_cards''
>>         from ...associations.rb:749:in `reviewers_score_cards''
>> Here are my models:
>> class Reviewer < ActiveRecord::Base
>>   has_many :candidates
>>   has_and_belongs_to_many :reviewers_score_cards
>> end
>> class ScoreCard < ActiveRecord::Base
>>   has_and_belongs_to_many :reviewers_score_cards,
>>     :join_table => "reviewers_score_cards"
>> end
>
> That should be something like:
>
> class Reviewer < ActiveRecord::Base
>   has_many :candidates
>   has_and_belongs_to_many :scorecards
> end
>
> class ScoreCard < ActiveRecord::Base
>   has_and_belongs_to_many :reviewers
> end
>
> And if you name your join table reviewers_scorecards (without the  
> second underscore) rails should pick it up automatically.
>
> Michael
Since the model is ScoreCard, the table would be score_cards and the  
join table would be named reviewers_score_cards.

I think the Reviewer model should have:
	has_and_belongs_to_many :score_cards


-Rob