关联模型中的 SequelizeEagerLoadingError答案

【问题标题】：SequelizeEagerLoadingError in associated models关联模型中的 SequelizeEagerLoadingError
【发布时间】：2018-12-18 01:26:45
【问题描述】：

当我在查询中添加包含时遇到问题，我不知道为什么。我有两个模型：User 和 Transaction

用户

    module.exports = (sequelize, DataTypes) => {
      var User = sequelize.define('User', {
        firstName: DataTypes.STRING,
        lastName: DataTypes.STRING,
        email: DataTypes.STRING
      }, {});
      User.associate = function(models) {
        User.hasMany(models.Transaction, {
          foreignKey: 'senderId',
          as: 'sender',
        }),
        User.hasMany(models.Transaction, {
          foreignKey: 'receiverId',
          as: 'receiver',
        })
      };
      return User;
    };

交易

  module.exports = (sequelize, DataTypes) => {
    var Transaction = sequelize.define('Transaction', {
      amount: DataTypes.INTEGER
    }, {});
    Transaction.associate = function(models) {
      Transaction.belongsTo(models.User, {
        foreignKey: 'senderId'
      }),
      Transaction.belongsTo(models.User, {
        foreignKey: 'receiverId'
      })
    };
    return Transaction;
  };

迁移后senderId和receiverId都在db中可用。

尝试查询：

  Transaction
    .findAll({
      where: { senderId: req.params.userId },
      include: [{
        model: User,
        as: 'sender',
      },{
        model: User,
        as: 'receiver',
      }],
    })

预期结果：

  {
    "transactions": [
      {
        "id": 2,
        "amount": 300,
        "sender": {
          "id": 2,
          "firstName": "John",
          "lastName": "Doe",
          "email": "jdoe+123@gmail.com",
        },
        "receiver": {
          "id": 3,
          "firstName": "John1",
          "lastName": "Doe1",
          "email": "jdoe+132@gmail.com",
        }
      },
      {
        "id": 3,
        "amount": 900,
        "sender": {
          "id": 2,
          "firstName": "John",
          "lastName": "Doe",
          "email": "jdoe+123@gmail.com",
        },
        "receiver": {
          "id": 3,
          "firstName": "John1",
          "lastName": "Doe1",
          "email": "jdoe+132@gmail.com",
        }
      }
    ]
  }

但我收到错误：SequelizeEagerLoadingError

他们的关联或查询有问题吗？

【问题讨论】：

标签： node.js express sequelize.js

【解决方案1】：

您需要为其中一个或两个关联添加别名，目前它们正在相互覆盖。比如：

module.exports = (sequelize, DataTypes) => {
  var Transaction = sequelize.define('Transaction', {
    amount: DataTypes.INTEGER
  }, {});
  Transaction.associate = function(models) {
    Transaction.belongsTo(models.User, {
      as: 'sender',
      foreignKey: 'senderId'
    }),
    Transaction.belongsTo(models.User, {
      as: 'receiver',
      foreignKey: 'receiverId'
    })
  };
  return Transaction;
};

【讨论】：