Sequelize——如何获得关联模型？答案

【问题标题】：Sequelize — how to get associated model?Sequelize——如何获得关联模型？
【发布时间】：2017-03-30 01:21:54
【问题描述】：

我有两个关联的模型（为了清楚起见，缩写）

const model = (sequelize, DataTypes) => {

  const User = sequelize.define('User', {
      fullName: {
        type: DataTypes.STRING,
        allowNull: false,
        validate: {
          notEmpty: true,
          len: [1,255]
        }
      }
    },
    {
      classMethods: {
        associate: function(models) {
          User.hasMany(models.Meeting, {as: 'chairedMeetings', foreignKey: 'chairmanId'})
        }
      }
    }
  )

  return User
}

和

const model = (sequelize, DataTypes) => {

  const Meeting = sequelize.define('Meeting', {
      title: {
        type: DataTypes.STRING,
        allowNull: false,
        validate: {
          notEmpty: true,
          len: [1,255]
        }
      }
    }, {
      classMethods: {
        associate: function(models) {
          Meeting.belongsTo(models.User, {as: 'chairman'})
        }
      }
    }
  )

  return Meeting
}

module.exports = model

我创建一个新会议，给定之前创建的用户id = 1，如下所示：

const data = {
  title: 'Some amazing meeting title',
  chairmanId: 1
}

Meeting.create(data, {include: [{all: true, nested: true}]}).then(meeting => {
  const chairmanId = meeting.get('chairmanId') // ===> this is 1 as expected
  const chairman = meeting.get('chairman')     // ===> but this is undefined
}

如何在无需手动通过关联和findOneid 的情况下返回关联记录？

【问题讨论】：

标签： javascript node.js associations sequelize.js

【解决方案1】：

好吧，想通了：

解决办法是在创建后做一个reload。

Meeting.create(data, {include: [{all: true, nested: true}]}).then(meeting => {
  const chairmanId = meeting.get('chairmanId') // ===> this is 1 as expected
  meeting.reload({include: [{all: true, nested: true}]}).then(reloadedMeeting => {
    const chairman = reloadedMeeting.get('chairman') // ===> is a user!
  })
}

我猜 sequelize 不会在创建后自动重新加载，以防你从不真正关心你刚刚创建的模型，而你只是想知道它被保存了。

【讨论】：