Question

我正在尝试设计模型，以便将聚会表与与会者表和项目表关联起来。这样，我可以使用Party_Id查询两个表。

很明显，我没有按照正确的方式进行操作...是否有任何关于我在哪里出错的想法？

提前谢谢！

派对模型

module.exports = function(sequelize, DataTypes) {
var Party = sequelize.define("Party", {
eventName: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
AuthenticationId: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
eventAddress: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
eventDate: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
eventTime: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
eventDescription: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
displayName: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
}
});

Party.associate = function(models) {
Party.hasMany(models.Attendee, {
  foreignKey: {
    allowNull: false
  },
  onDelete: "cascade"
});
};

return Party;
};

与会者模型：

module.exports = function(sequelize, DataTypes) {
var Attendee = sequelize.define("Attendee", {
AuthenticationId: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
},
displayName: {
  type: DataTypes.STRING,
  allowNull: false,
  validate: {
    len: [1]
  }
 }
});

Attendee.associate = function(models) {
 Attendee.hasMany(models.Item, {
  foreignKey: {
    allowNull: false
  },
  onDelete: "cascade"
 });
};

Attendee.associate = function(models) {
 Attendee.belongsTo(models.Party, {
  foreignKey: {
    allowNull: false
  },
  onDelete: "cascade"
 });
 };

return Attendee;
};

项目模型

    module.exports = function(sequelize, DataTypes) {
      var Item = sequelize.define("Item", {
        itemName: {
          type: DataTypes.STRING,
          allowNull: false,
          validate: {
            len: [1]
          }
        },
        qtyRequested: {
          type: DataTypes.INTEGER,
          allowNull: false,
          validate: {
            len: [1]
          }
        },
        qtyCommited: {
          type: DataTypes.INTEGER,
          allowNull: true,
          validate: {
            len: [1]
          }
        },
        hostAdded: {
          type: DataTypes.BOOLEAN,
          allowNull: true,
          validate: {
            len: [1]
          }
        },
        AuthenticationId: {
          type: DataTypes.STRING,
          allowNull: false,
          validate: {
            len: [1]
          }
        },
        displayName: {
          type: DataTypes.STRING,
          allowNull: false,
          validate: {
            len: [1]
          }
        }
      });

      Item.associate = function(models) {
        Item.belongsTo(models.Attendee, {
          foreignKey: {
            allowNull: false
          },
          onDelete: "cascade"
        });
      };

      return Item;
    };

这是返回错误的查询：

app.get("/parties/:id", (req, res) => {
 db.Party.findOne({
  where: { id: req.params.id },
    include: [
    {
      model: db.Attendee,
       include: [
        {
          model: db.Item
        }
      ]
    }
  ]
})
  .then(party => {
    console.log(party)
  })
  .catch(function(error) {
    console.log(error);
  });
});

错误：

   SequelizeEagerLoadingError: Item is not associated to Attendee!

Answer 1

已解决的问题：出于我要执行的操作，我必须按以下方式定义我的关联：

派对模式：

   Party.associate = function(models) {
Party.hasMany(models.Attendee, {
  foreignKey: {
    allowNull: false
  },
  onDelete: "cascade"
 });
};

与会者模型：

   Attendee.associate = function(models) {
     Attendee.hasMany(models.Item, {
       foreignKey: "attendeeAuthenticationId",
       allowNull: false,
       onDelete: "cascade"
     });
   };

项目模型：

    Item.associate = function(models) {
     Item.belongsTo(models.Attendee, {
      foreignKey: "attendeeAuthenticationId"
     });
    };

我的查询更改为：

 db.Party.findOne({
  where: { id: req.params.id },
  include: [
    {
      model: db.Attendee,
      include: [
        {
          model: db.Item
        }
      ]
    }
  ]
})

Answer 2

真正的问题是这样：

Attendee.associate = function(models) {
    Attendee.hasMany(models.Item, {
        foreignKey: {
            allowNull: false
        },
        onDelete: "cascade"
    });
};

Attendee.associate = function(models) { // <---- This will override the upper one
    Attendee.belongsTo(models.Party, {
        foreignKey: {
            allowNull: false
        },
        onDelete: "cascade"
    });
};

解决方案：

Attendee.associate = = function(models) { 

    Attendee.hasMany(models.Item, {
        foreignKey: {
            allowNull: false
        },
        onDelete: "cascade"
    });

    Attendee.belongsTo(models.Party, {
        foreignKey: {
            allowNull: false
        },
        onDelete: "cascade"
    });
};

为什么无法识别我的关联并导致SequelizeEagerLoadingError？

2 个答案: