Ruby on rails 4 rails 4如何使用外键和主键
如何设置以下关联:Ruby on rails 4 rails 4如何使用外键和主键,ruby-on-rails-4,Ruby On Rails 4,如何设置以下关联: class Midatum < ActiveRecord::Base # ..., diagn1, diagn2, diagn3 # sample data: # ..., "0123", nil ,"0124" # ..., "0123", nil ,"0124" # ..., "0123", "1123", nil belongs_to :icd9, :foreing_key => :diagn1 belongs_to :icd
class Midatum < ActiveRecord::Base
# ..., diagn1, diagn2, diagn3
# sample data:
# ..., "0123", nil ,"0124"
# ..., "0123", nil ,"0124"
# ..., "0123", "1123", nil
belongs_to :icd9, :foreing_key => :diagn1
belongs_to :icd9, :foreing_key => :diagn2
belongs_to :icd9, :foreing_key => :diagn3
end
class icd9 < ActiveRecord::Base
# icd9, description
# sample data:(unique)
#"0123", "some text"
#"0124", "some other text"
#"1123", "description text"
#"1133", "description text"
has_many :midata, :foreing_key => :icd9, :primary_key => :icd9
end
class Midatum:diagn1
属于:icd9,:foreing\u key=>:diagn2
属于:icd9,:foreing\u key=>:diagn3
结束
类icd9:icd9,:primary\u key=>:icd9
结束
这是行不通的。这对某人来说可能是显而易见的,但对我来说不是。数据库
是一个遗留数据库,只读。我需要建立这个assoc来处理数据。这个答案来自Rails专家,它确实解决了我的问题。我张贴它的情况下,其他人有同样的问题
belongs_to :icd9_a, :foreign_key => :diagn1, :class_name => "Icd9"
belongs_to :icd9_b, :foreign_key => :diagn2, :class_name => "Icd9"
belongs_to :icd9_c, :foreign_key => :diagn3, :class_name => "Icd9"
但这意味着您需要使用以下三种方法查询关联:
m=中腰第一
m、 icd9_a
m、 icd9_b
m、 icd9_c
同样,在Icd9类中,您需要三个具有唯一名称的独立关联:
class Icd9 < ActiveRecord::Base
self.primary_key = :icd9
has_many :midata_a, :foreign_key => :diagn1, :class_name => "Midatum"
has_many :midata_b, :foreign_key => :diagn2, :class_name => "Midatum"
has_many :midata_c, :foreign_key => :diagn3, :class_name => "Midatum"
end
self.primary_key = :icd9