如何在Rails 4中设置自定义字符串外键？

如何使用string 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 > 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 group name'

Answer 1

我想你应该使用Pharmaceutic belongs_to :pharmaceutic_group和PharmaceuticGroup has_many :pharmaceutics ，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, foreign_key: :group_code, primary_key: :code end