ROR中3路habtm的自定义数据库条目
我正在将现有的perl gtk应用程序转换为ROR应用程序
我有一个3路habtm关联模型。
class CustomerMaster "customer_phone_addres" has_and_belongs_to_many :phone_master, :join_table => "customer_phone_address" class AddressMaster "customer_phone_addres" has_and_belongs_to_many :phone_master, :join_table => "customer_phone_addres" class PhoneMaster "customer_phone_addres" has_and_belongs_to_many :address_master, :join_table => "customer_phone_addres" 连接表具有以下模式
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，它为address_master和phone_master提供输入
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
但是使用上面的关系模型，我在ROR的情况下得到两个条目
id|customer_master_id|phone_master_id|address_master_id 186769|182810|500775|nil| 186770|182810|nil|211935|
我需要保持与perl gtk应用程序的向后兼容性。 如何在连接表中而不是两个条目中获取该单个条目？
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
假设您正在使用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，您应该禁用遗留数据库模式的复数。 （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关联has_many :through ：
# 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，它运行得很好。 要创建关联：
CustomerPhoneAddress.create( :phone_master => PhoneMaster.first, :address_master => AddressMaster.first, :customer_master => CustomerMaster.first)
要查询关联：
IRB> a = AddressMaster.first => # IRB> a.customer_masters => [#] IRB> a.phone_masters => [#] IRB> a.customer_phone_addresses => [#]