Rails habtm 悲伤是我愚蠢还是 Rails bug？（绝望的 ; ）

发布于 2024-10-31 20:24:02 字数 10101 浏览 3 评论 0原文

大家好，

我在习惯关系方面遇到了一个奇怪的问题，老实说，我开始认为我可能偶然发现了 Rails 3 中的一些奇怪的错误。不过我肯定是疯了。我已经为此绞尽脑汁三天了，用谷歌搜索了我能想到的所有东西，但仍然找不到答案。

好的，情况是：

我正在创建一个 Rails 应用程序来替换 Java 应用程序和 PHP 应用程序（java 应用程序和 php 前端）。这将是一个分阶段的操作，第一阶段是 Rails 应用程序接管注册和计费。为此，Rails 应用程序必须在数据库中为 Java 和 PHP 应用程序创建数据。 Rails 应用程序本身使用 Devise 进行身份验证。

在database.yml 中，我定义了标准的3 个数据库，并为Java 应用程序数据库定义了一个连接。

以下是外部对象的模型定义片段（我只是创建常规 Rails 模型来与外部数据库对话）：

class Pushbroom::UserAccount < ActiveRecord::Base
  require 'digest/md5'
  require 'base64'

  establish_connection :pushbroom
  set_table_name :user_account
  set_primary_key :id

  has_and_belongs_to_many :user_roles, :join_table => 'pb_prod.users_roles', :class_name => 'Pushbroom::UserRole', :foreign_key => 'user_account_id', :association_foreign_key => 'user_role_id'
  belongs_to :user, :dependent => :destroy


  attr_accessible :user_roles, :admin_notes, :enabled, :username, :password_hash, :prefStore, :accepted_tos, :do_not_contact
end


class Pushbroom::UserRole < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_role
  set_primary_key :id

  has_and_belongs_to_many :user_accounts, :join_table => 'pb_prod.users_roles', :class_name => 'Pushbroom::UserAccount', :foreign_key => 'user_role_id', :association_foreign_key => 'user_account_id'


end

最后是我的 Rails 应用程序用户对象：

class User < ActiveRecord::Base

  after_create :send_welcome_email
  before_save :create_pushbroom_user_data

  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  belongs_to :pb_user_account, :class_name => "Pushbroom::UserAccount", :foreign_key => "pb_user_account_id", :dependent => :destroy, :autosave => true

  # Setup accessible (or protected) attributes for your model
  attr_accessible :first_name, :last_name, :username, :dob, :email, :password,         :password_confirmation, :remember_me

  validates_presence_of :first_name, :last_name, :username, :dob
  validates_date :dob, :on_or_after => lambda { 100.years.ago }, :on_or_after_message => "must be on or after #{100.years.ago.strftime('%m-%d-%Y')}" 
  validates_date :dob, :on_or_before => lambda { 13.years.ago }, :on_or_before_message => "must be on or before #{13.years.ago.strftime('%m-%d-%Y')}"

  def create_pushbroom_user_data
    pb_user = create_pushbroom_user
    pb_user_account = create_pushbroom_user_account(pb_user)
    pb_user_account.user_roles << Pushbroom::UserRole.find_by_name('user')
    self.pb_user_account = pb_user_account
  end

  def create_pushbroom_user
    pb_user = Pushbroom::User.new
    pb_user.attributes = self.attributes.slice(
      "email",
      "first_name",
      "last_name",
      "dob")

    pb_user
  end

def create_pushbroom_user_account(pb_user)
    pb_user_account = Pushbroom::UserAccount.new
    pb_user_account.enabled = true
    pb_user_account.password_hash =                 Pushbroom::UserAccount.create_password_digest(@plaintext_password, self.username)
    pb_user_account.username = self.username
    pb_user_account.user = pb_user

    pb_user_account
  end

看起来它应该很普通。这里唯一奇怪的是它们不在本机 Rails 数据库中，并且其中一个字段在关系表中被命名为“funny”。

因此，这是一个 Rails 控制台会话，我在其中创建一个 Rails 用户，调用该方法来创建外部对象，然后尝试保存：

ruby-1.9.2-p180 :001 > def user_fred
ruby-1.9.2-p180 :002?>       { 
ruby-1.9.2-p180 :003 >             :first_name => "Fred",
ruby-1.9.2-p180 :004 >             :last_name => "Flinstone",
ruby-1.9.2-p180 :005 >             :username => "fflint",
ruby-1.9.2-p180 :006 >             :dob => "1986-06-01",
ruby-1.9.2-p180 :007 >             :email => "[email protected]",
ruby-1.9.2-p180 :008 >             :password => "badpass"
ruby-1.9.2-p180 :009?>         }
ruby-1.9.2-p180 :010?>     end
 => nil 
ruby-1.9.2-p180 :011 > user = User.new(user_fred)
 => #<User id: nil, email: "[email protected]", encrypted_password:     "$2a$10$IiEOEoSnXIrP7VJAQYckfOVXuzm7Y5ZGo20ayLpSkHhz...", reset_password_token: nil, remember_created_at: nil, sign_in_count: 0, current_sign_in_at: nil, last_sign_in_at: nil, current_sign_in_ip: nil, last_sign_in_ip: nil, created_at: nil, updated_at: nil, first_name: "Fred", last_name: "Flinstone", username: "fflint", dob: "1986-06-01", pb_user_account_id: nil> 
ruby-1.9.2-p180 :012 > user.create_pushbroom_user_data
=> #<Pushbroom::UserAccount id: nil, created_by: nil, created_at: nil, updated_by: nil,     updated_at: nil, admin_notes: nil, enabled: true, username: "fflint", password_hash: "blah     blah", user_id: nil, prefStore: nil, accepted_tos: nil, do_not_contact: nil> 
ruby-1.9.2-p180 :013 > user.pb_user_account.user_roles
 => [#<Pushbroom::UserRole id: 1, created_by: "script", created_at: "2008-11-10     12:10:44", updated_by: "script", updated_at: "2008-11-10 12:10:44", admin_notes: "", name:     "user", description: "Generic User Role", conditional: false>] 
ruby-1.9.2-p180 :014 > user.save!
NoMethodError: undefined method `relation' for nil:NilClass
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activesupport-    3.0.5/lib/active_support/whiny_nil.rb:48:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/arel-    2.0.9/lib/arel/insert_manager.rb:22:in `insert'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/arel-    2.0.9/lib/arel/crud.rb:26:in `insert'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/associations/has_and_belongs_to_many_association.rb:76:in     `insert_record'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/associations/association_proxy.rb:151:in `send'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:306:in `block in     save_collection_association'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_collection.rb:431:in `block in     method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `block in method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `each'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_collection.rb:431:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:297:in `save_collection_association'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:163:in `block in add_autosave_association_callbacks'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activesupport-3.0.5/lib/active_support/callbacks.rb:415:in `_run_create_callbacks'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/callbacks.rb:281:in `create'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/persistence.rb:246:in `create_or_update'
... 18 levels...
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/callbacks.rb:277:in `create_or_update'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/persistence.rb:56:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/validations.rb:49:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/attribute_methods/dirty.rb:30:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:245:in `block in save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/transactions.rb:292:in `block in with_transaction_returning_status'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in     `transaction'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:207:in `transaction'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:290:in `with_transaction_returning_status'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:245:in `save!'
  from (irb):14
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands/console.rb:44:in `start'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands/console.rb:8:in `start'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands.rb:23:in `<top (required)>'
  from script/rails:6:in `require'
  from script/rails:6:in `<main>'ruby-1.9.2-p180 :015 >

如果我删除角色分配，一切都会很顺利（查找、保存、销毁等），但是其次，我试图挽救角色，坦率地说，我不明白这个消息，一切都变得非常高。它知道它的角色，我可以告诉没有零对象。。基本上，如果我还没有秃顶，我就会把头发拔掉；）

非常感谢对此的任何见解！

杰拉尔德·

P.S.这里还问http://railsforum.com/viewtopic.php?id=43647会如果找到重复的答案。

原文

Greetings all,

I'm having a weird problem with a habtm relationship and honestly I'm beginning to think I may have stumbled upon some weird bug in rails 3. Surely I'm crazy though. I've been beating my head against the wall on this for 3 days, have googled everything under the sun I can think of and still can't come up with an answer.

Ok, the situation:

I'm creating a Rails app to replace both a Java app and a PHP app (java application and php front-end). This is going to be a phased operation with the first phase being the Rails application takes over registration and billing. In order to do this, the Rails application must create data in the databases for the Java and PHP apps. The Rails application itself is using Devise for authentication.

In database.yml I have my standard 3 databases defined and also a connection defined for the Java apps database.

Here are pieces of the model definitions for the external object (I'm just creating regular rails models to talk to the external databases):

class Pushbroom::UserAccount < ActiveRecord::Base
  require 'digest/md5'
  require 'base64'

  establish_connection :pushbroom
  set_table_name :user_account
  set_primary_key :id

  has_and_belongs_to_many :user_roles, :join_table => 'pb_prod.users_roles', :class_name => 'Pushbroom::UserRole', :foreign_key => 'user_account_id', :association_foreign_key => 'user_role_id'
  belongs_to :user, :dependent => :destroy


  attr_accessible :user_roles, :admin_notes, :enabled, :username, :password_hash, :prefStore, :accepted_tos, :do_not_contact
end


class Pushbroom::UserRole < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_role
  set_primary_key :id

  has_and_belongs_to_many :user_accounts, :join_table => 'pb_prod.users_roles', :class_name => 'Pushbroom::UserAccount', :foreign_key => 'user_role_id', :association_foreign_key => 'user_account_id'


end

And finally my Rails application user object:

class User < ActiveRecord::Base

  after_create :send_welcome_email
  before_save :create_pushbroom_user_data

  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  belongs_to :pb_user_account, :class_name => "Pushbroom::UserAccount", :foreign_key => "pb_user_account_id", :dependent => :destroy, :autosave => true

  # Setup accessible (or protected) attributes for your model
  attr_accessible :first_name, :last_name, :username, :dob, :email, :password,         :password_confirmation, :remember_me

  validates_presence_of :first_name, :last_name, :username, :dob
  validates_date :dob, :on_or_after => lambda { 100.years.ago }, :on_or_after_message => "must be on or after #{100.years.ago.strftime('%m-%d-%Y')}" 
  validates_date :dob, :on_or_before => lambda { 13.years.ago }, :on_or_before_message => "must be on or before #{13.years.ago.strftime('%m-%d-%Y')}"

  def create_pushbroom_user_data
    pb_user = create_pushbroom_user
    pb_user_account = create_pushbroom_user_account(pb_user)
    pb_user_account.user_roles << Pushbroom::UserRole.find_by_name('user')
    self.pb_user_account = pb_user_account
  end

  def create_pushbroom_user
    pb_user = Pushbroom::User.new
    pb_user.attributes = self.attributes.slice(
      "email",
      "first_name",
      "last_name",
      "dob")

    pb_user
  end

def create_pushbroom_user_account(pb_user)
    pb_user_account = Pushbroom::UserAccount.new
    pb_user_account.enabled = true
    pb_user_account.password_hash =                 Pushbroom::UserAccount.create_password_digest(@plaintext_password, self.username)
    pb_user_account.username = self.username
    pb_user_account.user = pb_user

    pb_user_account
  end

Seems like it should be pretty vanilla. The ONLY weirdness here is that they aren't in the native rails database and one of the fields is named funny in the relations table.

So here's a rails console session where I create a rails user, call the method to create the external objects, then try to save:

ruby-1.9.2-p180 :001 > def user_fred
ruby-1.9.2-p180 :002?>       { 
ruby-1.9.2-p180 :003 >             :first_name => "Fred",
ruby-1.9.2-p180 :004 >             :last_name => "Flinstone",
ruby-1.9.2-p180 :005 >             :username => "fflint",
ruby-1.9.2-p180 :006 >             :dob => "1986-06-01",
ruby-1.9.2-p180 :007 >             :email => "[email protected]",
ruby-1.9.2-p180 :008 >             :password => "badpass"
ruby-1.9.2-p180 :009?>         }
ruby-1.9.2-p180 :010?>     end
 => nil 
ruby-1.9.2-p180 :011 > user = User.new(user_fred)
 => #<User id: nil, email: "[email protected]", encrypted_password:     "$2a$10$IiEOEoSnXIrP7VJAQYckfOVXuzm7Y5ZGo20ayLpSkHhz...", reset_password_token: nil, remember_created_at: nil, sign_in_count: 0, current_sign_in_at: nil, last_sign_in_at: nil, current_sign_in_ip: nil, last_sign_in_ip: nil, created_at: nil, updated_at: nil, first_name: "Fred", last_name: "Flinstone", username: "fflint", dob: "1986-06-01", pb_user_account_id: nil> 
ruby-1.9.2-p180 :012 > user.create_pushbroom_user_data
=> #<Pushbroom::UserAccount id: nil, created_by: nil, created_at: nil, updated_by: nil,     updated_at: nil, admin_notes: nil, enabled: true, username: "fflint", password_hash: "blah     blah", user_id: nil, prefStore: nil, accepted_tos: nil, do_not_contact: nil> 
ruby-1.9.2-p180 :013 > user.pb_user_account.user_roles
 => [#<Pushbroom::UserRole id: 1, created_by: "script", created_at: "2008-11-10     12:10:44", updated_by: "script", updated_at: "2008-11-10 12:10:44", admin_notes: "", name:     "user", description: "Generic User Role", conditional: false>] 
ruby-1.9.2-p180 :014 > user.save!
NoMethodError: undefined method `relation' for nil:NilClass
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activesupport-    3.0.5/lib/active_support/whiny_nil.rb:48:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/arel-    2.0.9/lib/arel/insert_manager.rb:22:in `insert'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/arel-    2.0.9/lib/arel/crud.rb:26:in `insert'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/associations/has_and_belongs_to_many_association.rb:76:in     `insert_record'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/associations/association_proxy.rb:151:in `send'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:306:in `block in     save_collection_association'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_collection.rb:431:in `block in     method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `block in method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `each'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_proxy.rb:216:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/associations/association_collection.rb:431:in `method_missing'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:297:in `save_collection_association'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/autosave_association.rb:163:in `block in add_autosave_association_callbacks'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activesupport-3.0.5/lib/active_support/callbacks.rb:415:in `_run_create_callbacks'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/callbacks.rb:281:in `create'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/persistence.rb:246:in `create_or_update'
... 18 levels...
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/callbacks.rb:277:in `create_or_update'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/persistence.rb:56:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/validations.rb:49:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/attribute_methods/dirty.rb:30:in `save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:245:in `block in save!'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-    3.0.5/lib/active_record/transactions.rb:292:in `block in with_transaction_returning_status'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in     `transaction'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:207:in `transaction'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:290:in `with_transaction_returning_status'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/activerecord-3.0.5/lib/active_record/transactions.rb:245:in `save!'
  from (irb):14
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands/console.rb:44:in `start'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands/console.rb:8:in `start'
  from /Users/gander/.rvm/gems/ruby-1.9.2-p180@sms2/gems/railties-3.0.5/lib/rails/commands.rb:23:in `<top (required)>'
  from script/rails:6:in `require'
  from script/rails:6:in `<main>'ruby-1.9.2-p180 :015 >

If I remove the role assignment, everything is just peachy (finds, saves, destroys, etc), but the second I try to save roles everything blows sky-high with this message that, frankly, I don't get. It knows its got the roles, there is no nil object that I can tell. . .and basically if I wasn't already bald I'd be pulling my hair out ; )

Any insight into this is EXTREMELY appreciated!

Gerald

P.S. Also asked here http://railsforum.com/viewtopic.php?id=43647 Will duplicate answer if found.

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樱花落人离去 2024-11-07 20:24:02

在这上我傻了 4 天之后，我终于发现了问题：Rails (habtm) 没有能力确定用于外部关系表的数据库。我也找到了答案，而且味道也不难闻！这里有一个关于该过程的完整线程：http://groups.google。 com/group/rubyonrails-talk/browse_thread/thread/c5655d0442039ccd

答案是什么？ has_many :through - 我从来没有仔细研究过这个功能，但它实际上是一个非常好的功能（即使在其他情况下也是如此）。

基本上，这只是允许我创建一个代表关系的模型类。因为我有一个模型类，所以我可以显式指定要连接的数据库。

为了子孙后代，代码如下：

class Pushbroom::UsersRolesRelationship < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :users_roles

  belongs_to :user_account
  belongs_to :user_role
end

class Pushbroom::UserAccount < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_account
  set_primary_key :id

  has_many :users_roles_relationships
  has_many :user_roles, :through => :users_roles_relationships, :source => :user_role
end

class Pushbroom::UserRole < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_role
  set_primary_key :id

  has_many :users_roles_relationships
  has_many :user_accounts, :through => :users_roles_relationships, :source => :user_account
end

并如此使用：

def add_subscription_plan_roles_to_pb_user_account(pb_user_account)
    roles_granted = pb_user_account.user.subscriptions.first.subscription_plan.roles_granted
    pb_user_account.user_roles = roles_granted
end

感谢很多人帮助我让这列火车再次行驶！我的所有测试都通过了，并且似乎有效，但如果您发现有问题，请仍然告诉我。

谢谢！
杰拉尔德

After beating myself silly for 4 days on this I finally found the problem: Rails (habtm) doesn't have the ability to determine the database to use for external relation tables. I also found the answer, and it doesn't even smell bad! There's a whole thread on the process here: http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/c5655d0442039ccd

The answer? has_many :through - something I'd never taken much of a look at, but it is actually a pretty nice feature (even in other circumstances).

Basically this just allows me to create a model class which represents the relationship. And since I have a model class for it I can explicitly specify the database to connect to.

For posterity sake, here's the code:

class Pushbroom::UsersRolesRelationship < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :users_roles

  belongs_to :user_account
  belongs_to :user_role
end

class Pushbroom::UserAccount < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_account
  set_primary_key :id

  has_many :users_roles_relationships
  has_many :user_roles, :through => :users_roles_relationships, :source => :user_role
end

class Pushbroom::UserRole < ActiveRecord::Base

  establish_connection :pushbroom
  set_table_name :user_role
  set_primary_key :id

  has_many :users_roles_relationships
  has_many :user_accounts, :through => :users_roles_relationships, :source => :user_account
end

And is used thusly:

def add_subscription_plan_roles_to_pb_user_account(pb_user_account)
    roles_granted = pb_user_account.user.subscriptions.first.subscription_plan.roles_granted
    pb_user_account.user_roles = roles_granted
end

Thanks a ton folks for helping me get this train moving again! All my tests are passing and it seems to be working, but if you see something wrong, please do still let me know.

Thanks!
Gerald

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