Ne pas obtenir les clés primaires avec des objets associés dans Rails

Question

Notez que les ID sont nuls lorsque j'obtiens les pays du produit. Je suis sur Rails 3.1. quelquun sait pourquoi cela se passe?

>> p = Product.first 
    Product Load (1.3ms) SELECT `products`.* FROM `products` LIMIT 1 
=> #<Product id: 1549, context_date: "2011-10-01 00:00:00", expiration_date: "2013-04-13 16:13:57", blurb: "do you like '", created_at: "2011-10-13 16:13:57", updated_at: "2011-10-13 16:13:57", product_type_id: 31, approved_at: nil, state: "waiting", archived_at: nil, name: "some product name", custom_name: "Product with '", secret: "secret", ups_owner_id: "4d911fc87b074638be000008", avatar_file_name: nil, avatar_content_type: nil, avatar_file_size: nil, avatar_updated_at: nil, is_global: false, ups_author_id: "4d911fc87b074638be000017", parent_id: nil, product_child_type_id: nil, finished_at: nil> 
>> p.countries 
    Country Load (0.9ms) SELECT `countries`.* FROM `countries` INNER JOIN `product_countries` ON `countries`.`id` = `product_countries`.`country_id` WHERE `product_countries`.`product_id` = 1549 
=> [#<Country id: nil, name: "Argentina", iso_two_letter_code: "AR", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Brazil", iso_two_letter_code: "BR", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Chile", iso_two_letter_code: "CL", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Colombia", iso_two_letter_code: "CO", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Costa Rica", iso_two_letter_code: "CR", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Dominican Republic", iso_two_letter_code: "DO", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Mexico", iso_two_letter_code: "MX", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Paraguay", iso_two_letter_code: "PY", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Peru", iso_two_letter_code: "PE", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">, #<Country id: nil, name: "Venezuela", iso_two_letter_code: "VE", created_at: "2010-09-24 19:02:43", updated_at: "2010-09-24 19:02:43">] 

Une autre chose étrange que je remarque est que la clé primaire imprimera réellement si je boucle et le vérifie. Donc, si je suis dans le modèle de produit et faire:

self.countries.each do |c| 
    logger.info "c.id = #{c.id}" 
end 

Je reçois en fait les clés primaires. Cependant, je l'ai remarqué à l'origine parce que la clé primaire du pays semble être nulle en essayant de saisir ses associations et par conséquent ne renvoie toujours rien. Par exemple:

 self.countries.each do |c| 
     logger.info "c.id = #{c.id}" 
     logger.info "c.country_groups = #{c.country_groups.inspect}" 
     end 

cela dans les Génère Rails journal:

c.id = 101 
    CountryGroup Load (0.6ms) SELECT `country_groups`.* FROM `country_groups` INNER JOIN `countries_country_groups` ON `country_groups`.`id` = `countries_country_groups`.`country_group_id` WHERE `countries_country_groups`.`country_id` IS NULL 
c.country_groups = [] 

Je suis encore assez confus au sujet de pourquoi il est la vérification de country_id IS NULL

Answer 1

est bien ici aussi étrange. Pas beaucoup de temps pour étudier pourquoi mais j'avais

attr_accessor :_id 

Dans mon modèle de pays depuis que je l'habitude de lire dans ces données de MongoDB. Enlever cela a résolu le problème puisque je n'utilise plus MongoDB.