sequelize.js - 在 Sequelize ORM 框架中加入没有关联的查询

Question

我可以在没有在 Seuqelize 中定义关联的情况下进行连接查询吗？

我尝试通过 Sequelize 进行如下 sql 查询

SELECT * FROM MessageRecipient INNER JOIN MESSAGE ON MessageRecipient.messageIdno = MESSAGE.Idno 

我确实通过在使用 findAll 时使用添加的“include”来实现的，如下所示，我必须在使用 include 之前定义关联

消息.js

var Message = sequelize.define('Message', {
 idno: {
  type: DataTypes.INTEGER,
  primaryKey: true,
  autoIncrement: true 
},
subject: DataTypes.STRING,
messageBody: DataTypes.STRING,
creatorId: DataTypes.INTEGER,
parentMessageId: DataTypes.INTEGER,
expiryDate:DataTypes.DATE,
isActive:DataTypes.INTEGER}, {
classMethods: {
  associate: function (models) { 
    Message.hasMany(models.MessageRecipient, { foreignKey: 'idno' });
  }}}); 
return ChatMessage;
};

消息接收者.js

var MessageRecipient = sequelize.define('MessageRecipient', {
 idno: {
  type: DataTypes.INTEGER,
  primaryKey: true,
  autoIncrement: true 
},
recipientId: DataTypes.INTEGER,
recipientGroupId: DataTypes.INTEGER,
messageId: DataTypes.INTEGER,
isRead:DataTypes.INTEGER
}, {
classMethods: {
  associate: function (models) { 
    MessageRecipient.belongsTo(models.Message, { foreignKey: 'messageId' });
  }
}
  }); return MessageRecipient;

findAll 包含

db.MessageRecipient
      .findAll({
        include: [{
          model: db.Message,
          required: true
        }]
      })
      .then((MessageRecipients) => {
        res.json(MessageRecipients);
      })
      .error((error) => {
        res.sendStatus(500);
      });

我会得到我想要的查询结果，如下所示

[
  {
    "idno": 1,
    "recipientId": null,
    "recipientGroupId": 1,
    "messageId": 1,
    "isRead": 0,
    "createdAt": "2017-04-14T01:24:31.000Z",
    "updatedAt": "2017-04-14T01:24:31.000Z",
    "ChatMessage": {
      "idno": 1,
      "subject": "my message subject",
      "messageBody": "my message content here",
      "creatorId": 1,
      "parentMessageId": 0,
      "expiryDate": null,
      "isActive": 1,
      "createdAt": "2017-04-14T01:24:30.000Z",
      "updatedAt": "2017-04-14T01:24:30.000Z"
    }
  }
]

如果我没有在 findAll 之前定义关联，我会得到错误

Unhandled rejection Error: ChatMessage is not associated to ChatMessageRecipient!

我怎样才能跳过 hasmany,belong 部分并仍然得到像上面一样的漂亮结果？
有没有解决方法可以做到这一点？

谢谢

Answer 1

我已经搜索过 the documentation并发现无法指定您加入的字段。据我所知，标准查询无法做到这一点。您要么必须进行单独(且效率低下)的查询，要么必须使用原始查询:

sequelize.query('SELECT * FROM MessageRecipient INNER JOIN MESSAGE ON MessageRecipient.messageIdno = MESSAGE.Idno').then(([results, metadata]) => {
  // ...
})

这个例子来自 the documentation也。