Activerecord应用实例——多表关联查询

 

关系：

class Company < ActiveRecord::Base

  has_many :regist_infos

end

class RegistInfo < ActiveRecord::Base

   belongs_to:company           # company_id

   belongs_to:b2bsite             # b2bsite_id

   has_many:post_infos                

end

class PostInfo < ActiveRecord::Base

   belongs_to:regist_info          # regist_info_id

   belongs_to:product            # product_id    

end

class Product < ActiveRecord::Base

   belongs_to :company          # company_id

   has_many:post_infos                       

end

 

class B2bsite < ActiveRecord::Base

   has_many:regist_infos                  

end

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应用以上这些关系，简化查询语句：

- @company.regist_infos.each do |info|

   %table

     %tr

        %td{:width=>"16%", :align=>"center", :valign=>"middle"}

           = B2bsite.find( info.b2bsite_id ).name

        %td{:width=>"20%",:align=>"left",:valign=>"middle"}

           = "已注册"            if info.regist_state == 1 

           = "已通过邮箱验证"    if info.regist_state == 2 

           = "已完成"            if info.regist_state == 3 

        %td{:width=>"15%",:align=>"left",:valign=>"middle"}

           = info.posted_product

        %td{:width=>"15%",:align=>"left",:valign=>"middle"}

           = info.posted_info 

        %td{:width=>"20%",:align=>"left",:valign=>"middle"}

           - info.post_infos.each do |p| 

              = Product.find( p.product_id ).title     if p.post_type == 2

              %br

        %td{:width=>"20%",:align=>"left",:valign=>"middle"}              

           - info.post_infos.each do |p| 

              = Product.find( p.product_id ).name    if p.post_type == 1

              %br

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