模型的has_many用户（一个特定的角色类型） [英] model has_many users(of a specific role type)
本文介绍了模型的has_many用户（一个特定的角色类型）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个pretty的标准色器件的用户模型模式与角色，是一个多对多的模式userRoles：
#teacher或学生
CREATE_TABLE角色，：力=＆GT;真做| T |
t.string名
结束
CREATE_TABLEuser_roles：力=＆GT;真做| T |
t.integerUSER_ID
t.integerROLE_ID
结束
add_indexuser_roles，[ROLE_ID]：名称=＆GT; index_user_roles_on_role_id
add_indexuser_roles，[user_ID的]：名称=＆GT; index_user_roles_on_user_id
CREATE_TABLE用户，：力=＆GT;真做| T |
t.string电子邮件，：默认=＆GT; ：空=＆GT;假
t.stringencrypted_password：默认=＆GT; ：空=＆GT;假
........更多的东西....
结束
add_index用户，[电子邮件]：名称=＆GT; index_users_on_email：独特=＆GT;真正
add_index用户，[reset_password_token]：名称=＆GT; index_users_on_reset_password_token：独特=＆GT;真正
结束
该角色是教师和学生。我想创建一个 clazz所（如学校班级）模型多对多的学生（用户与学生的角色）和多对多的老师（用户与教师的角色）
我认为这将是这个样子，但不能完全得到它：
轨道摹支架clazz所名称：字符串时间：日期时间的has_many：用户的has_many（类学生）：用户（型教师）我该怎么办的最后两？难道我创建的has_many，：通过关联迁移（teacherClass和studentClass）第一？或者是有一个辅助的方法？
也许我只是找不到合适的教程或例子，所以我可以提前使用的这些以及...感谢一个
这是我的尝试@Cody Caughlan的答案
了解更多信息Schema.rb：
的ActiveRecord :: Schema.define（：版本=＆GT; 20130523111519）办
CREATE_TABLEclass_instructions：力=＆GT;真做| T |
t.string名
t.datetime时间
t.integerUSER_ID
t.datetimecreated_at：空=＆GT;假
t.datetime的updated_at：空=＆GT;假
结束
add_indexclass_instructions，[user_ID的]：名称=＆GT; index_class_instructions_on_user_id
CREATE_TABLE角色，：力=＆GT;真做| T |
t.string名
t.datetimecreated_at：空=＆GT;假
t.datetime的updated_at：空=＆GT;假
结束
CREATE_TABLE歌曲，：力=＆GT;真做| T |
t.string称号
t.string内容
t.datetimecreated_at：空=＆GT;假
t.datetime的updated_at：空=＆GT;假
t.integerUSER_ID
t.stringfractionRe presentation
t.stringmeasureRe presentation
结束
CREATE_TABLEuser_roles：力=＆GT;真做| T |
t.integerUSER_ID
t.integerROLE_ID
t.datetimecreated_at：空=＆GT;假
t.datetime的updated_at：空=＆GT;假
结束
add_indexuser_roles，[ROLE_ID]：名称=＆GT; index_user_roles_on_role_id
add_indexuser_roles，[user_ID的]：名称=＆GT; index_user_roles_on_user_id
CREATE_TABLE用户，：力=＆GT;真做| T |
t.string电子邮件，：默认=＆GT; ：空=＆GT;假
t.stringencrypted_password：默认=＆GT; ：空=＆GT;假
t.stringreset_password_token
t.datetimereset_password_sent_at
t.datetimeremember_created_at
t.integersign_in_count：默认=＆GT; 0
t.datetimecurrent_sign_in_at
t.datetimelast_sign_in_at
t.stringcurrent_sign_in_ip
t.stringlast_sign_in_ip
结束
add_index用户，[电子邮件]：名称=＆GT; index_users_on_email：独特=＆GT;真正
add_index用户，[reset_password_token]：名称=＆GT; index_users_on_reset_password_token：独特=＆GT;真正
结束
User.rb模式：
类用户的LT;的ActiveRecord :: Base的
#DEVISE STUFF
＃==协会
的has_many：user_roles，：依赖=＆GT; ：破坏
的has_many：角色：通过=＆GT; ：user_roles
的has_many：歌曲
＃==实例方法
高清thisUsersID
self.id
结束
高清student_classes（class_instruction_name）
member_classes（class_instruction_name，学生）
结束
高清teacher_classes（class_instruction_name）
member_classes（class_instruction_name，角色::教师）
结束
私人
高清member_classes（class_instruction_name，类型）
ClassInstruction \
.joins（：USER_ROLE）\
。凡（[user_role.user_id =？，ID]）\
.joins（INNER JOIN ON roles.id = user_roles.role_id角色）\
。凡（roles.name =？，类型）\
。凡（class_instruction.name =？，class_instruction_name）
结束
结束
user_role.rb模式：
类UserRole＆LT;的ActiveRecord :: Base的
belongs_to的：用户
belongs_to的：角色
的has_many：class_instructions，：依赖=＆GT; ：破坏
结束
role.rb模型
类角色＆LT;的ActiveRecord :: Base的
的has_many：user_roles，：依赖=＆GT; ：破坏
结束
class_instruction.rb模型（名字是'SS'and'math-101'）
类ClassInstruction＆LT;的ActiveRecord :: Base的
belongs_to的：USER_ROLE
结束
错误堆栈
加载开发环境（Rails的3.2.2）
1.9.3-429页：001〕 U = User.find（3）
用户负载（的3.2ms）选择用户。*从用户WHERE用户，ID=？ LIMIT 1 [身份证，3]
=＆GT; ＃＆lt;使用者ID：3，电子邮件：stu@test.org，encrypted_password：$ 2A $ 10 $ 2DxWWV34BRFJoLboYyWCIeXEtCPYOSe8JqpTmFU6W2i1 ......，reset_password_token：无，reset_password_sent_at：无，remember_created_at：无，sign_in_count：0，current_sign_in_at：无，last_sign_in_at：无，current_sign_in_ip：无，last_sign_in_ip：无＆GT;
1.9.3-429页：002＆GT; U.student_classes（数学-101）。全部
ClassInstruction负荷（为0.2ms）选择class_instructions。* FROMclass_instructionsINNER JOINuser_rolesONuser_roles。ID=class_instructions。user_role_idINNER JOIN ON roles.id = user_roles.role_id WHERE角色（ user_role.user_id = 3）和（roles.name ='学生'）和（class_instruction.name ='数学-101）
:: sqlite3的的SQLException：没有这样的列：user_role.user_id：选择class_instructions*从角色class_instructionsINNER JOINuser_rolesONuser_roles，ID=class_instructionsuser_role_idINNER JOIN角色。 ID = user_roles.role_id WHERE（user_role.user_id = 3）和（roles.name ='学生'）和（class_instruction.name ='数学-101）
ActiveRecord的:: StatementInvalid：SQLite3的::的SQLException：没有这样的列：user_role.user_id：。选择class_instructions* FROMclass_instructionsINNER JOINuser_rolesONuser_roles，ID=class_instructionsuser_role_id作者：参加关于roles.id = user_roles.role_id角色WHERE（user_role.user_id = 3）和（roles.name ='学生'）和（class_instruction.name ='数学-101）
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in'初始化'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in'新'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in`prepare
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:246:in `块exec_query
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `块日志
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.2/lib/active_support/notifications/instrumenter.rb:20:in `仪器
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:275:in '登录'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:242:in `exec_query
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:460:in '选择'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:18:in `SELECT_ALL
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:63:in `SELECT_ALL
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/querying.rb:38:in `块的find_by_sql
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/explain.rb:40:in`logging_query_plan
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/querying.rb:37:in `的find_by_sql
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:171:in `exec_queries
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:160:in `块to_a
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/explain.rb:33:in`logging_query_plan
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:159:in `to_a
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation/finder_methods.rb:159:in '所有'
从（IRB）：2
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands/console.rb:47:in'开始'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands/console.rb:8:in'开始'
从/Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands.rb:41:in`＆LT;顶（必填）＆GT;
从脚本/导轨：6：在'要求'
从脚本/导轨：6：`＆lt;主＆GT;1.9.3-429页：003＆GT;
解决方案
首先，类是一个保留字在Ruby中，所以你将不能够使用它作为一个型号名称。
http://www.java2s.com/code /红宝石/语言-基础/ Rubysreservedwords.htm
所以，选择一个不同的名称。在这样的我都做的情况下 clazz所。
对于数据模型 - 是的，你会在指定的ActiveRecord类的定义，而不是在迁移的关系
它不清楚你的 clazz所模型的样子。但我会假设它有2列：名称和 user_role_id 。你可能要拔出名称到一个单独的表，并将它换成像 clazz_id - 。但现在，我们将保持平坦
我会用一个实例方法建立关联，但你也许能够得到疯狂的的has_many 定义。
clazz类＆LT;的ActiveRecord :: Base的
belongs_to的：USER_ROLE
结束
类用户
＃==协会
的has_many：user_roles，：依赖=＆GT; ：破坏
的has_many：角色：通过=＆GT; ：user_roles
＃==实例方法
高清student_classes（clazz_name）
member_classes（clazz_name，角色::学生）
结束
高清teacher_classes（clazz_name）
member_classes（clazz_name，角色::教师）
结束
私人
高清member_classes（clazz_name，类型）
clazz所\
.joins（：USER_ROLE）\
。凡（[user_role.user_id =？，ID]）\
.joins（INNER JOIN ON roles.id = user_roles.role_id角色）\
。凡（roles.name =？，类型）\
。凡（clazzes.name =？，clazz_name）
结束
结束
类UserRole
的has_many：clazzes，：依赖=＆GT; ：破坏
结束
类角色
的has_many：user_roles，：依赖=＆GT; ：破坏
结束
因此，这将让你做这样的事情：
用户= User.find（99）＃我们知道这个用户是学生
user.student_classes（社会科学101）所有。
类似的东西。
I have a pretty standard devise user model schema with roles and a many to many model for userRoles:
#teacher or student
create_table "roles", :force => true do |t|
t.string "name"
end
create_table "user_roles", :force => true do |t|
t.integer "user_id"
t.integer "role_id"
end
add_index "user_roles", ["role_id"], :name => "index_user_roles_on_role_id"
add_index "user_roles", ["user_id"], :name => "index_user_roles_on_user_id"
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
........more stuff....
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true
end
The roles are teacher and student. I want to create a Clazz (as in school class) model with many to many students (users with role of students) and many to many teachers (users with role of teachers).
I think it would look something like this, but can't quite get it:
rails g scaffold Clazz name:string time:datetime has_many:users(of type student) has_many:users(of type teacher) How do I do the last two? Do I create the has_many, :through association migrations (teacherClass and studentClass) first? or is there a helper method?
Maybe I just couldn't find an appropriate tutorial or example, so i could use one of those as well... Thanks in advance
This is more information about my attempt at @Cody Caughlan 's answer
Schema.rb :
ActiveRecord::Schema.define(:version => 20130523111519) do
create_table "class_instructions", :force => true do |t|
t.string "name"
t.datetime "time"
t.integer "user_id"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
add_index "class_instructions", ["user_id"], :name => "index_class_instructions_on_user_id"
create_table "roles", :force => true do |t|
t.string "name"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
create_table "songs", :force => true do |t|
t.string "title"
t.string "content"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "user_id"
t.string "fractionRepresentation"
t.string "measureRepresentation"
end
create_table "user_roles", :force => true do |t|
t.integer "user_id"
t.integer "role_id"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
add_index "user_roles", ["role_id"], :name => "index_user_roles_on_role_id"
add_index "user_roles", ["user_id"], :name => "index_user_roles_on_user_id"
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true
end
User.rb model :
class User < ActiveRecord::Base
#DEVISE STUFF
#== Associations
has_many :user_roles, :dependent => :destroy
has_many :roles, :through => :user_roles
has_many :songs
#== Instance Methods
def thisUsersID
self.id
end
def student_classes(class_instruction_name)
member_classes(class_instruction_name, 'Student')
end
def teacher_classes(class_instruction_name)
member_classes(class_instruction_name, Role::TEACHER)
end
private
def member_classes(class_instruction_name, type)
ClassInstruction \
.joins(:user_role) \
.where(["user_role.user_id = ?", id]) \
.joins("INNER JOIN roles ON roles.id = user_roles.role_id") \
.where("roles.name = ?", type) \
.where("class_instruction.name = ?", class_instruction_name)
end
end
user_role.rb model:
class UserRole < ActiveRecord::Base
belongs_to :user
belongs_to :role
has_many :class_instructions, :dependent => :destroy
end
role.rb model
class Role < ActiveRecord::Base
has_many :user_roles, :dependent => :destroy
end
class_instruction.rb model (names are 'ss' and'math-101')
class ClassInstruction < ActiveRecord::Base
belongs_to :user_role
end
Error Stack
Loading development environment (Rails 3.2.2)
1.9.3-p429 :001 > U = User.find(3)
User Load (3.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1 [["id", 3]]
=> #<User id: 3, email: "stu@test.org", encrypted_password: "$2a$10$2DxWWV34BRFJoLboYyWCIeXEtCPYOSe8JqpTmFU6W2i1...", reset_password_token: nil, reset_password_sent_at: 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>
1.9.3-p429 :002 > U.student_classes('math-101').all
ClassInstruction Load (0.2ms) SELECT "class_instructions".* FROM "class_instructions" INNER JOIN "user_roles" ON "user_roles"."id" = "class_instructions"."user_role_id" INNER JOIN roles ON roles.id = user_roles.role_id WHERE (user_role.user_id = 3) AND (roles.name = 'Student') AND (class_instruction.name = 'math-101')
SQLite3::SQLException: no such column: user_role.user_id: SELECT "class_instructions".* FROM "class_instructions" INNER JOIN "user_roles" ON "user_roles"."id" = "class_instructions"."user_role_id" INNER JOIN roles ON roles.id = user_roles.role_id WHERE (user_role.user_id = 3) AND (roles.name = 'Student') AND (class_instruction.name = 'math-101')
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: user_role.user_id: SELECT "class_instructions".* FROM "class_instructions" INNER JOIN "user_roles" ON "user_roles"."id" = "class_instructions"."user_role_id" INNER JOIN roles ON roles.id = user_roles.role_id WHERE (user_role.user_id = 3) AND (roles.name = 'Student') AND (class_instruction.name = 'math-101')
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `initialize'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `new'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/sqlite3-1.3.7/lib/sqlite3/database.rb:91:in `prepare'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:246:in `block in exec_query'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activesupport-3.2.2/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:242:in `exec_query'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:460:in `select'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:18:in `select_all'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:63:in `select_all'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/querying.rb:38:in `block in find_by_sql'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/explain.rb:40:in `logging_query_plan'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/querying.rb:37:in `find_by_sql'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:171:in `exec_queries'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:160:in `block in to_a'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/explain.rb:33:in `logging_query_plan'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation.rb:159:in `to_a'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/activerecord-3.2.2/lib/active_record/relation/finder_methods.rb:159:in `all'
from (irb):2
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands/console.rb:47:in `start'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands/console.rb:8:in `start'
from /Users/phycom06/.rvm/gems/ruby-1.9.3-p429/gems/railties-3.2.2/lib/rails/commands.rb:41:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'1.9.3-p429 :003 >
解决方案
Firstly, Class is a reserved word in Ruby so you will not be able to use it as a Model name.
http://www.java2s.com/Code/Ruby/Language-Basics/Rubysreservedwords.htm
So pick a different name. In cases like this I have done Clazz.
As for the data model - yes you would specify the relationships in the ActiveRecord class definition and not in the migration.
Its not clear what your Clazz model looks like. But I will assume it has 2 columns: name and a user_role_id. You'd probably want to pull out the name into a separate table and have it be replaced with like a clazz_id - but for now we will keep it flat.
I will use an instance method to build the associations, but you might be able to get crazy in the has_many definitions.
class Clazz < ActiveRecord::Base
belongs_to :user_role
end
class User
#== Associations
has_many :user_roles, :dependent => :destroy
has_many :roles, :through => :user_roles
#== Instance Methods
def student_classes(clazz_name)
member_classes(clazz_name, Role::STUDENT)
end
def teacher_classes(clazz_name)
member_classes(clazz_name, Role::TEACHER)
end
private
def member_classes(clazz_name, type)
Clazz \
.joins(:user_role) \
.where(["user_role.user_id = ?", id]) \
.joins("INNER JOIN roles ON roles.id = user_roles.role_id") \
.where("roles.name = ?", type) \
.where("clazzes.name = ?", clazz_name)
end
end
class UserRole
has_many :clazzes, :dependent => :destroy
end
class Role
has_many :user_roles, :dependent => :destroy
end
So this will enable you to do something like:
user = User.find(99) # we know this user is a student
user.student_classes('Social Studies 101').all
Something like that.
这篇关于模型的has_many用户（一个特定的角色类型）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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