如何通过 MongoDB (Mongoose) 中的“_id”字段查找文档的数组项？

Question

我有以下架构（NestJS + Mongoose）：

@Schema({ timestamps: true })
export class Listing {
  @Prop({
        type: [{
            bidderId: { type: Types.ObjectId, required: true, select: false, ref: User.name, index: true },
            amount: { type: Number, required: true },
            date: { type: Date, required: true }
        }],
        select: false
    })
        bids!: Bid[]
}

所以基本上每个listing 文档都有一个bids 数组。
现在我注意到 mongoDB（或 mongoose）会自动为我放入 bids 数组的每个投标项目创建 _id 字段。

我的问题是，如果我有一个出价的_id，我如何从列表的出价数组中查询它的项目？类似：

  // Adding a new bid to the listing, and retrieving the updated listing
  const listingWithAddedBid = await this.listingModel.findByIdAndUpdate(listingId, {
    $push: {
        bids: {
            $each: [{
                amount: bidInfo.amount,
                bidderId: new Types.ObjectId(user.id),
                date: new Date()
            }],
            $sort: { amount: -1 }
        }
    }
}, { new: true })

  // Getting the new bid's _id from the array (it will be at index 0 because we sort buy amount)
  const newBidId = listingWithAddedBid.bids[0]._id

  // here how can I query the entire bid item from the array with 'newBidId'? this won't work
  this.listingModel.findById(newBidId) // returns null

Answer 1

https://docs.mongodb.com/manual/tutorial/query-array-of-documents/ https://docs.mongodb.com/manual/indexes/#default-_id-index

this.listingModel.findOne({ "bids._id": newBidId, {}, {}, (error, doc) =>
        {
         if (error) {
                ....
              }
              if (doc) {
                ....
              } else {
                ...//'Not Found';
              }
        });