Node.js 如何使用Sequelize.js在表之间建立多对多关系？

我想使用Sequelize.js在事件表和用户表之间建立多对多关系。一个用户可以参与多个事件，并且一个事件有多个参与者。因此，我带来了一个event_user的中间表，并创建了它的模型

以下是所有3种型号：

我的用户\u model.js：

var EventUser = require('./event_user_model.js');

//_______________________Init & Config Sequelize__________________

const Sequelize = require("sequelize");
const sequelize = new Sequelize('db', 'root', '', {
  host: 'localhost',
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});
//____________Declare table structure ________________________

var User = sequelize.define('user', {
  id: {
    type: Sequelize.STRING,
    primaryKey: true, 
    },
  password: { 
    type: Sequelize.STRING,
  },
  email: {
    type: Sequelize.STRING
  },   
  user_id: { //Foreign Key. Do I even need to put it here at all?
    type: Sequelize.INTEGER,
    references: {
      model: "events_user",
      key: "user_id",
     } 
  },

}, {
  freezeTableName: true
});

//__________________Establish relationships with other tables_________


User.belongsTo(EventUser,{foreignKey:user_id});

//_____________________________________________________________________

User.sync({force:true}).then(function () {
  return User.create({
    id:'ORD0',
    password: 'mypass',
    email: 'whatever@gmail.com',
    user_id:1    
  });
}).then(c => {
    console.log("User Created", c.toJSON());
})
.catch(e => console.error(e));

//______________________________________________________________________

module.exports = User;

var EventUser = require('./event_user_model.js');

//______________Init & Config Sequelize_________
const Sequelize = require("sequelize");
const sequelize = new Sequelize('millesime_admin', 'root', '', {
  host: 'localhost',
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});
//______________________Declare table structure __________________

var Event = sequelize.define('event', {    
  eventid: { 
    type: Sequelize.INTEGER,
    primaryKey: true, 
    autoIncrement: true,        
    },
  date: {
    type: Sequelize.DATE
  },
  title: {
    type: Sequelize.STRING,
  },   
  event_id: { //Foreign Key . Do I even need to put it here at all?
    type: Sequelize.INTEGER,
    references: {
      model: "event_user",
      key: "event_id" // Surely here I do something wrong!!
    }
  },     

}, {
  freezeTableName: true 
});

//____________Establish relationships with other tables_________

Event.belongsTo(EventUser, {foreignKey: event_id});

//________________________Create table____________
Event.sync().then(function () {

  return Event.create({
    eventid:1,
    title: 'Event1',
    date: new Date(24, 9, 2016),
    event_id: 1,        
  });
}).then(c => {
    console.log("Created event", c.toJSON());
}).catch(e => console.error(e));

//________________________________________________________
    module.exports = Event; 

My events_model.js：

var EventUser = require('./event_user_model.js');

//_______________________Init & Config Sequelize__________________

const Sequelize = require("sequelize");
const sequelize = new Sequelize('db', 'root', '', {
  host: 'localhost',
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});
//____________Declare table structure ________________________

var User = sequelize.define('user', {
  id: {
    type: Sequelize.STRING,
    primaryKey: true, 
    },
  password: { 
    type: Sequelize.STRING,
  },
  email: {
    type: Sequelize.STRING
  },   
  user_id: { //Foreign Key. Do I even need to put it here at all?
    type: Sequelize.INTEGER,
    references: {
      model: "events_user",
      key: "user_id",
     } 
  },

}, {
  freezeTableName: true
});

//__________________Establish relationships with other tables_________


User.belongsTo(EventUser,{foreignKey:user_id});

//_____________________________________________________________________

User.sync({force:true}).then(function () {
  return User.create({
    id:'ORD0',
    password: 'mypass',
    email: 'whatever@gmail.com',
    user_id:1    
  });
}).then(c => {
    console.log("User Created", c.toJSON());
})
.catch(e => console.error(e));

//______________________________________________________________________

module.exports = User;

var EventUser = require('./event_user_model.js');

//______________Init & Config Sequelize_________
const Sequelize = require("sequelize");
const sequelize = new Sequelize('millesime_admin', 'root', '', {
  host: 'localhost',
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});
//______________________Declare table structure __________________

var Event = sequelize.define('event', {    
  eventid: { 
    type: Sequelize.INTEGER,
    primaryKey: true, 
    autoIncrement: true,        
    },
  date: {
    type: Sequelize.DATE
  },
  title: {
    type: Sequelize.STRING,
  },   
  event_id: { //Foreign Key . Do I even need to put it here at all?
    type: Sequelize.INTEGER,
    references: {
      model: "event_user",
      key: "event_id" // Surely here I do something wrong!!
    }
  },     

}, {
  freezeTableName: true 
});

//____________Establish relationships with other tables_________

Event.belongsTo(EventUser, {foreignKey: event_id});

//________________________Create table____________
Event.sync().then(function () {

  return Event.create({
    eventid:1,
    title: 'Event1',
    date: new Date(24, 9, 2016),
    event_id: 1,        
  });
}).then(c => {
    console.log("Created event", c.toJSON());
}).catch(e => console.error(e));

//________________________________________________________
    module.exports = Event; 

和我的事件_user_model.js：

var User = require('./users_model.js');
var Event= require('./events_model.js');

//______________________________Initialize & Config Sequelize__________________
const Sequelize = require("sequelize");
const sequelize = new Sequelize('millesime_admin', 'root', '', {
  host: 'localhost',
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }
});
//_______________Declare table structure ________________________
var EventUser = sequelize.define('eventuser', {    
  eventuserid: { 
    type: Sequelize.INTEGER,
    primaryKey: true,
    autoIncrement: true,
    },
  user_id: {
    type: Sequelize.INTEGER,
    references: {
      model: "users",
      key: "id",
     }   
  },
  event_id: { 
    type: Sequelize.INTEGER,
    references: {
       model: "event",
       key: "eventid",
     }   
  },
 reservationConfirmation:{
    type:Sequelize.BOOLEAN,
 },
 attendance:{
    type:Sequelize.BOOLEAN
 },
},
{
  freezeTableName: true 
});

//___________________Establish relationships with other tables_________

EventUser.hasMany(User, {foreignKey:id});
//EventUser.hasMany(Event, {forignKey:eventid});
//__________________________Create table_______________________
EventUser.sync( /*{force: true}*/ ).then(function () {
  return EventUser.create({
    eventuserid:1,
    event_id:1,
    user_id: 1,
    reservationConfirmation: true,
    attendance: true    
  });
}).then(c => {
    console.log("Created", c.toJSON());
}).catch(e => console.error(e));   
//___________________________________________________
 module.exports = EventUser;

请参见下文：“与联接表的多对多关联”

例如：

UserProject = sequelize.define('user_project', {
  role: Sequelize.STRING
});
User.belongsToMany(Project, { through: UserProject });
Project.belongsToMany(User, { through: UserProject });    

见文件：

---

您所做的第一件错误事情是在每个模型文件中创建新的Sequelize实例。您需要创建一个文件，在其中创建

sequelize

实例，该实例将导入到每个模型定义文件中。在您的情况下，结构可以如下所示

- models
    - sequelize.js
    - event.js
    - user.js
    - eventUser.js

每个文件都应该是这样的：

// sequelize.js
var Sequelize = require('sequelize');

var sequelize = new Sequelize(
    'millesime_admin',
    'root',
    '',
    {
        host: 'localhost',
        dialect: 'mysql',
        pool: {
            max: 5,
            min: 0,
            idle: 10000
       }
    }
);

module.exports = sequelize;

现在，当您创建sequelize实例时，就可以定义模型了

// event.js
var sequelize = require('./sequelize');

var Event = sequelize.define(...);

module.exports = Event;

// user.js
var sequelize = require('./sequelize');

var User = sequelize.define(...);

module.exports = User;

现在，您可以创建最后一个模型

EventUser

，以及

Event

和

User

之间的多对多关系。此关系将在发生

eventUser

模型定义的

eventUser.js

文件中创建

// eventUser.js
var sequelize = require('./sequelize');
var User      = require('./user');
var Event     = require('./event');

var EventUser = sequelize.define(...);

User.belongsToMany(Event, { through: EventUser } );
Event.belongsToMany(User, { through: EventUser } );

---

谢谢你的回答！我修改了，现在，在我的event_model.js上，我有：User.belongtomany（event，{through:EventUser}）；在我的event_模型上，jsthis:event.belongtomany（User，{through:EventUser}）；我的intermedite模型：var EventUser=sequelize.define（'EventUser'，{…}）；但是，不幸的是，它仍然不起作用。你说它不起作用是什么意思？发生了一些错误或者发生了什么？是的，我得到了以下错误：event.belongsToMany调用了一些不是Sequelize.model实例的内容感谢您的回答！我遵循了您关于Sequelize初始化的建议。但是，就我自己而言，我注意到使用自定义id（例如：eventid）对续集不太友好（或者是这样，但我不知道如何正确处理它）。我使用EventUser.belongsTo（Event）；仅在我的event_user_model.js中。现在关系已经建立。再次感谢你！：）

eventId

primary key有什么问题？@piotrbienias我有-也许你能帮我。我和Emma仍在努力理解如何使用Sequelize实现这种多对多关系。如果你给出了一个好的答案，我可能也会奖励你一笔赏金！我现在正在看这个问题，给我一点时间；）@谢谢你！如果有帮助的话。如果需要，您可以使用不同的示例（例如书籍和作者等）。