ruby-on-rails – 如何在Rails 4中设置自定义字符串外键？

发布时间：2020-12-17 03:05:32 所属栏目：百科来源：网络整理

导读：如何使用字符串foreign_key设置关联以正确设置has_one？ class Pharmaceutic ActiveRecord::Base has_one :pharmaceutic_group,foreign_key: "code"endclass PharmaceuticGroup ActiveRecord::Base belongs_to :pharmaceutic,primary_key: 'code'end Pharmac

如何使用字符串foreign_key设置关联以正确设置has_one？

class Pharmaceutic < ActiveRecord::Base
  has_one :pharmaceutic_group,foreign_key: "code"
end

class PharmaceuticGroup < ActiveRecord::Base
  belongs_to :pharmaceutic,primary_key: 'code'
end

>> Pharmaceutic.last.pharmaceutic_group                                                                                        
  Pharmaceutic Load (0.3ms)  SELECT `pharmaceutics`.* FROM `pharmaceutics` ORDER BY `pharmaceutics`.`id` DESC LIMIT 1
  PharmaceuticGroup Load (0.3ms)  SELECT `pharmaceutic_groups`.* FROM `pharmaceutic_groups` WHERE `pharmaceutic_groups`.`code` = 2 ORDER BY `pharmaceutic_groups`.`id` ASC LIMIT 1
=> nil
>> Pharmaceutic
=> Pharmaceutic(id: integer,package_type: integer,group_code: string)
>> PharmaceuticGroup
=> PharmaceuticGroup(id: integer,code: string,name: string)

例如,当：Pharmaceutic有group_code：aaa和PharmaceuticGroup有代码：aaa我想得到Pharmaceutic.last.pharmaceutic_group.name => ‘AAA组名’

解决方法

我想你应该使用Pharmaceutic belongs_to：pharmaceuticalic_group和PharmaceuticGroup has_many：pharmaceuticalics,像这样：

class Pharmaceutic < ActiveRecord::Base
  belongs_to :pharmaceutic_group,foreign_key: :group_code,primary_key: :code
end

class PharmaceuticGroup < ActiveRecord::Base
  has_many :pharmaceutics,primary_key: :code
end

（编辑：李大同）

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