mongoose中使用pre中间件删除相关记录答案

【问题标题】：Delete related records using pre middleware in mongoosemongoose中使用pre中间件删除相关记录
【发布时间】：2021-12-06 16:11:10
【问题描述】：

我有 3 个架构，包括：

建筑

const BuildingSchema = mongoose.Schema({
  address: { type: String, required: true },
  numberOfRooms: { type: Number, default: 0 },
});

房间

const RoomSchema = mongoose.Schema({
  roomNumber: { type: Number, required: true, unique: false },
  building: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "Building",
    required: true,
    unique: false,
  },
});

协议

const AgreementSchema = mongoose.Schema({
  agreementNumber: { type: Number, unique: true },
  room: {
    type: mongoose.Schema.Types.ObjectId,
    ref: "Room",
    required: true,
    unique: false,
  },
});

我的场景是在删除建筑物之后

与建筑相关的所有房间
与房间相关的所有协议

也将被删除，目前我知道如何删除与建筑相关的房间：

BuildingSchema.pre("deleteOne", function (next) {
  Room.deleteMany({ building: this._conditions._id }).exec();
  next();
});

那么我该如何使用pre 中间件呢？

我的猫鼬版：^6.0.12

谢谢！

【问题讨论】：

标签： javascript mongodb express mongoose

【解决方案1】：

BuildingSchema.pre("remove", function (next) {
  Room.deleteMany({ building: this._conditions._id }).exec();
  next();
});

记得使用 building.remove() mongoose 基础函数移除建筑物：)

【讨论】：

Schema.remove() api 已弃用，因此我改用 deleteOne

【解决方案2】：

这是我的解决方案。

BuildingSchema.pre("deleteOne", async function (next) {
  const buildingId = this._conditions._id;
  await Room.find({ building: buildingId }, (err, rooms) => {
    rooms.map(async (item) => {
      await Agreement.deleteMany({ room: item._id }); // => Delete all Agreements related to Room
    });
  }).clone();
  await Room.deleteMany({ building: buildingId }); // => Delete all Rooms related to Building
});

【讨论】：