使用聚合 mongodb mongoose 将集合子子文档与其他集合子文档连接起来

Question

所以，我有这种模型

const produkSchema = new mongoose.Schema({
    nama_produk: String,
    etalase: {type: mongoose.Schema.Types.ObjectID, ref: 'kategori'},
    kategori: {type: mongoose.Schema.Types.ObjectID, ref: 'kategori'},
    jenis: {type: mongoose.Schema.Types.ObjectID, ref: 'kategori.jenis'},
    bahan: String,
    warna: String,
    deskripsi: String,
    foto_produk: [String],
    harga: Number,
    link_bukalapak: String,
    link_shopee: String,
    link_tokopedia: String,
}, {
    weights: {
        nama_produk: 5,
    },
    timestamps: true
})

const tokoSchema = new mongoose.Schema({
    username: {type: String, trim: true},
    password: {type: String, required: true, select: false},
    merek: String,
    listMerek: [{type: mongoose.Schema.Types.ObjectID, ref: 'produk'}],
    deskripsi: String,
    follower: [{type: mongoose.Schema.Types.ObjectID, ref: 'user'}],
    email: {type: String, trim: true, unique: true},
    instagram: String,
    whatsapp: String,
    website: String,
    alamat: String,
    foto_profil: String,
    bukalapak: String,
    shopee: String,
    tokopedia: String,
    fotoktp: String,
    banner: [{
        gambar: {type: String, required: true, trim: true},
        order: {type: Number, required: true},
    }],
    produk: [produkSchema],
    etalase: [{type: mongoose.Schema.Types.ObjectID, ref: 'kategori'}],
    approve: {type: Number, default: 0}, // 0: pending, 1: reject, 2: approve
    populer: {type: Boolean, default: false},
}, {timestamps: true});

exports.toko = mongoose.model("toko", tokoSchema);

const jenisSchema = new mongoose.Schema({
    label: String,
    gambar: String,
}, {timestamps: true})

const kategoriSchema = new mongoose.Schema({
    label: String,
    gambar: String,
    jenis: [jenisSchema]
}, {timestamps: true});

所以我想加入的是toko.produk.jenis 和kategori.jenis，但是如您所知，猫鼬不能在子文档之间填充，我尝试过toko.find().populate("produk.jenis", "label") 但它显示错误Schema hasn't been registered for model "kategori.jenis". Use mongoose.model(name, schema) 任何查询建议？我试过了

{
    $lookup: {
           "from": "kategoris",
           "localField": "produk.jenis",
           "foreignField": "jenis",
           "as": "jenisnya"
        }
}

但它似乎不起作用，而是返回一个空数组。我该怎么办？我应该重新排列我的架构吗？

Answer 1

你可以试试这个，

• $match你的条件
• $unwind解构produk数组
• $lookup 带管道
  • $unwind解构jenis数组
  • $match匹配jenis._id
  • $project 仅显示 _id 和 label
• $unwind 在路径中解构 produk.jenisnya
• $group by _id 并推入produk

db.toko.aggregate([
  { $match: { _id: ObjectId("5f1d77aca53cb13980324c73") } },
  { $unwind: "$produk" },
  {
    $lookup: {
      from: "kategoris",
      as: "produk.jenisnya",
      let: { pjid: "$produk.jenis" },
      pipeline: [
        { $unwind: "$jenis" },
        { $match: { $expr: { $eq: ["$$pjid", "$jenis._id"] } } },
        { $project: { "jenis._id": 1, "jenis.label": 1 } }
      ]
    }
  },
  { $unwind: { path: "$produk.jenisnya" } },
  {
    $group: {
      _id: "$_id",
      produk: { $push: "$produk" },
      // you can add otehr fields as well like alamat
      alamat: { $first: "$alamat" }
    }
  }
])

Playground