Question

我正在将现有的perl gtk应用转换为ROR应用

我有一个3路habtm关联模型。

class CustomerMaster < ActiveRecord::Base
  has_and_belongs_to_many :address_master, :join_table => "customer_phone_addres"
  has_and_belongs_to_many :phone_master, :join_table => "customer_phone_address"

class AddressMaster < ActiveRecord::Base
    has_and_belongs_to_many :customer_master, :join_table => "customer_phone_addres"
    has_and_belongs_to_many :phone_master, :join_table => "customer_phone_addres"

class PhoneMaster < ActiveRecord::Base
  has_and_belongs_to_many :customer_master, :join_table => "customer_phone_addres"
  has_and_belongs_to_many :address_master, :join_table => "customer_phone_addres"

联接表具有以下架构

CREATE TABLE customer_phone_address
(
  id bigserial NOT NULL,
  customer_master_id bigint,
  phone_master_id bigint,
  address_master_id bigint,
  CONSTRAINT customer_phone_address_pkey PRIMARY KEY (id),
  CONSTRAINT address FOREIGN KEY (address_master_id)
      REFERENCES address_master (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT customer FOREIGN KEY (customer_master_id)
      REFERENCES customer_master (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT phone FOREIGN KEY (phone_master_id)
      REFERENCES phone_master (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT uniq_cust_phone_address UNIQUE (customer_master_id, phone_master_id, address_master_id)
)

我为customer_master #new创建了一个嵌套表单，其中包含address_master和phone_master的输入

最初对于perl gtk应用程序，在join_table中只为客户，地址和电话的每个条目创建一个条目

id|customer_master_id|phone_master_id|address_master_id
186767|182774|500773|210683

然而，使用上述关系模型，在ROR的情况下我得到两个条目

id|customer_master_id|phone_master_id|address_master_id
186769|182810|500775|nil|
186770|182810|nil|211935|

我需要保持对perl gtk应用程序的向后兼容性。 如何在联接表中输入单个条目而不是两个条目？

我认为这个问题类似于 https://stackoverflow.com/questions/5507150/custom-join-3-tables-usage-in-rails-2-3-8

Answer 1

假设您使用的是Rails 3。

当您的连接表只有2个外键时，您应该使用habtm。对于大多数情况，has_many :through会更灵活。

在您的情况下，您应该为连接表创建一个模型。首先，您应该禁用旧数据库模式的复数。（我以为你已经这样做了）。

# In config/application.rb
config.active_record.pluralize_table_names = false

按惯例创建一个连接表，即CustomerPhoneAddress（我将给它一个更有意义的名称）：

# customer_phone_address.rb
class CustomerPhoneAddress < ActiveRecord::Base
  belongs_to :address_master
  belongs_to :customer_master
  belongs_to :phone_master
end

最后，将您的模型与has_many和has_many :through：

相关联

# address_master.rb
class AddressMaster < ActiveRecord::Base
  has_many :customer_phone_addresses
  has_many :customer_masters, :through => :customer_phone_addresses
  has_many :phone_masters, :through => :customer_phone_addresses
end

# customer_master.rb
class CustomerMaster < ActiveRecord::Base
  has_many :customer_phone_addresses
  has_many :address_masters, :through => :customer_phone_addresses
  has_many :phone_masters, :through => :customer_phone_addresses
end

# phone_master.rb
class PhoneMaster < ActiveRecord::Base
  has_many :customer_phone_addresses
  has_many :customer_masters, :through => :customer_phone_addresses
  has_many :phone_masters, :through => :customer_phone_addresses
end

我测试了代码并且它运行良好。要创建关联：

CustomerPhoneAddress.create(
  :phone_master => PhoneMaster.first,
  :address_master => AddressMaster.first,
  :customer_master => CustomerMaster.first)

查询关联：

IRB> a = AddressMaster.first
=> #<AddressMaster id: 1, created_at: "2011-12-07 15:23:07", updated_at: "2011-12-07 15:23:07">
IRB> a.customer_masters
=> [#<CustomerMaster id: 1, created_at: "2011-12-07 15:23:15", updated_at: "2011-12-07 15:23:15">]
IRB> a.phone_masters
=> [#<PhoneMaster id: 1, created_at: "2011-12-07 15:23:19", updated_at: "2011-12-07 15:23:19">]
IRB> a.customer_phone_addresses
=> [#<CustomerPhoneAddress id: 1, address_master_id: 1, customer_master_id: 1, phone_master_id: 1, created_at: "2011-12-07 15:24:01", updated_at: "2011-12-07 15:24:01">]

ROR中3路habtm的自定义数据库条目

1 个答案: