使用聚合mongodb mongoose将collections子文档与其他collections子文档连接

如何解决使用聚合mongodb mongoose将collections子文档与其他collections子文档连接

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,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'}],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,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,jenis: [jenisSchema]
},{timestamps: true});

所以我想加入的是toko.produk.jenis和kategori.jenis，但众所周知，猫鼬无法在子文档之间填充，我尝试了toko.find().populate("produk.jenis","label")，但显示错误{{ 1}}有任何查询建议吗？我尝试过

Schema hasn't been registered for model "kategori.jenis". Use mongoose.model(name,schema)

，但似乎不起作用，而是返回一个空数组。我该怎么办？我应该重新排列架构吗？

解决方法

您可以尝试一下

• $match您的条件
• $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produk.jenisnya中解构
• $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" }
    }
  }
])

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