在Rails中HABTM和连接表的问题(Problem with HABTM and join table in Rails)

 我有一个简单的模型： 
 
class User < ActiveRecord::Base
   has_and_belongs_to_many :roles
end

class Role < ActiveRecord::Base
   has_and_belongs_to_many :users
end
 
 我创建了一个简单的连接表： 
 
class CreateUsersRoles < ActiveRecord::Migration
  def self.up
    create_table :users_roles, :id => false do |t|
      t.integer :user_id
      t.integer :role_id

      t.timestamps
    end
  end

  def self.down
    drop_table :users_roles
  end
end
 
 迁移后，shema.rb正在关注： 
 
create_table "roles", :force => true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
end

create_table "users", :force => true do |t|
    t.string   "login"
    t.string   "password"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

create_table "users_roles", :id => false, :force => true do |t|
  t.integer  "user_id"
  t.integer  "role_id"
  t.datetime "created_at"
  t.datetime "updated_at"
end
 
 这些条目以相同的顺序显示在“schema.rb”中 
 
 我按照以下方式安排了固定装置： 
 
# roles.yml 
user:
  name: user

admin:
  name: admin

moderator:
  name: moderator

# users.yml
User1:
  login: User1
  password: User1
  roles: user

User2:
  login: User2
  password: User2
  roles: admin, moderator

User3:
  login: User3
  password: User3
  roles: moderator
 
 并遇到一个问题：在“rake db：fixtures：load”rails上抱怨连接表的名称： 
 
 
 
 SQLite3 :: SQLException：没有这样的表：roles_users：DELETE FROM“roles_users”WHERE 1 = 1 
 
 
 问题是 - 为什么它期望“roles_users”，而表是“users_roles”？ 

I have a simple model:
 
class User < ActiveRecord::Base
   has_and_belongs_to_many :roles
end

class Role < ActiveRecord::Base
   has_and_belongs_to_many :users
end
 
I have created a simple join table:
 
class CreateUsersRoles < ActiveRecord::Migration
  def self.up
    create_table :users_roles, :id => false do |t|
      t.integer :user_id
      t.integer :role_id

      t.timestamps
    end
  end

  def self.down
    drop_table :users_roles
  end
end
 
After migration, shema.rb is following:
 
create_table "roles", :force => true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
end

create_table "users", :force => true do |t|
    t.string   "login"
    t.string   "password"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

create_table "users_roles", :id => false, :force => true do |t|
  t.integer  "user_id"
  t.integer  "role_id"
  t.datetime "created_at"
  t.datetime "updated_at"
end
 
The entries are presented here in the same order, as in "schema.rb"
 
I arranged fixtures in following way:
 
# roles.yml 
user:
  name: user

admin:
  name: admin

moderator:
  name: moderator

# users.yml
User1:
  login: User1
  password: User1
  roles: user

User2:
  login: User2
  password: User2
  roles: admin, moderator

User3:
  login: User3
  password: User3
  roles: moderator
 
And got a problem: on "rake db:fixtures:load" rails complains about name of a join table:
 
 
 
SQLite3::SQLException: no such table: roles_users: DELETE FROM "roles_users" WHERE 1=1
 
 
The question is - why it expects "roles_users", while the table is "users_roles" ?

原文：https://stackoverflow.com/questions/3288330