Rails：belongs_to 和 has_many 使用非标准 ID

发布于 2024-10-22 11:04:30 字数 935 浏览 1 评论 0原文

我有两个模型，项目和产品，如下所示：

irb(main):007:0> Item
=> Item(id: integer, identification_number: string, production_date: date, 
        created_at: datetime, updated_at: datetime, going_in: boolean)
irb(main):008:0> Product
=> Product(id: integer, sku: string, barcode_identification: string, 
           created_at: datetime, updated_at: datetime)

将其视为特定产品的项目。

我已设法通过引用特定产品 (Product.find(1).items) 的所有项目，

class Product < ActiveRecord::Base
  has_many :items, :foreign_key => "identification_number", 
                   :primary_key => "barcode_identification"
end

但我似乎无法引用特定项目的产品。这就是我现在所得到的：

class Item < ActiveRecord::Base
  set_primary_key :identification_number
  belongs_to :product, :foreign_key => "barcode_identification"
end

就我对数据库的理解而言，这应该可行。但事实并非如此。也许我在这里错过了一些东西？我对 Rails 相当陌生（大约一个月或更短时间。）

原文

I've got two models, Item and Product as follows:

irb(main):007:0> Item
=> Item(id: integer, identification_number: string, production_date: date, 
        created_at: datetime, updated_at: datetime, going_in: boolean)
irb(main):008:0> Product
=> Product(id: integer, sku: string, barcode_identification: string, 
           created_at: datetime, updated_at: datetime)

Think of this as an item is of a particular product.

I've managed to refer all the items of a particular product (Product.find(1).items) via

class Product < ActiveRecord::Base
  has_many :items, :foreign_key => "identification_number", 
                   :primary_key => "barcode_identification"
end

but I can't seem to refer the Product of a particular item.
This is what I've got now:

class Item < ActiveRecord::Base
  set_primary_key :identification_number
  belongs_to :product, :foreign_key => "barcode_identification"
end

And as far as my understanding re: databases are concerned, that should work. Except that it doesn't. Maybe I'm missing out on something here? I'm fairly new to rails (around a month or less.)

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清风无影 2024-10-29 11:04:30

它必须是belongs_to吗？既然您指定了主键和外键，为什么不呢

class Product < ActiveRecord::Base
  has_many :items, :foreign_key => "identification_number", 
                   :primary_key => "barcode_identification"
end

class Item < ActiveRecord::Base
  has_one :product, :foreign_key => "barcode_identification", 
                    :primary_key => "identification_number"
end

Does it have to be a belongs_to? Since you're specifying both primary and foreign key, why not

class Product < ActiveRecord::Base
  has_many :items, :foreign_key => "identification_number", 
                   :primary_key => "barcode_identification"
end

class Item < ActiveRecord::Base
  has_one :product, :foreign_key => "barcode_identification", 
                    :primary_key => "identification_number"
end

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久隐师 2024-10-29 11:04:30

您的 items 表中必须有一个外键。
我假设条形码_识别_id 是项目表中的一列（外键）。
如果您有其他列，则只需将其替换为该列即可。

尝试这样：

class Product < ActiveRecord::Base
  set_primary_key :barcode_identification
  has_many :items, :foreign_key => "barcode_identification_id"
end

class Item < ActiveRecord::Base
  set_primary_key :identification_number
  belongs_to :product
end

You must have a foreign key in your items table.
I'm assuming barcode_identification_id is a column (foreign key) in items table.
If you have some other column then just replace it with that.

Try like this:

class Product < ActiveRecord::Base
  set_primary_key :barcode_identification
  has_many :items, :foreign_key => "barcode_identification_id"
end

class Item < ActiveRecord::Base
  set_primary_key :identification_number
  belongs_to :product
end

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