如何使用Mongoose在另一个集合中查找子查询文档。

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英文:

How to lookup subquery documents with another collection moongoose

问题

我需要两次加入用户集合，因为同一用户将发布产品并将购买用户的详细信息作为子文档。

产品模式：

  1. {
  2.     product_title: String,
  3.     product_desc: String,
  4.     Product_purchased:[
  5.         {
  6.             userid: mongoose.Schema.ObjectId,
  7.             purchased_date: Date
  8.         }]
  9.     posteduserId: mongoose.Schema.ObjectId
  10. }

用户模式：

  1. {
  2.     _id: userId,
  3.     name: String,
  4.     Pic: String
  5. }

示例文档：

  1. [
  2.     {
  3.         "product_title":"title",
  4.         "product_desc":"desc",
  5.         "Product_purchased":[
  6.             {
  7.                 "userid":"5d4hvh7duc7c7c8d9scbe",
  8.                 "name":"name",
  9.                 "Pic":"url",
  10.                 "purchased_date":"Date"
  11.             },
  12.             {
  13.                 "userid":"5d4hvh7duc7c7c8d9scbe",
  14.                 "name":"name",
  15.                 "Pic":"url",
  16.                 "puchased_date":"Date"
  17.             }
  18.         ],
  19.         "posteduserId": "5d4hvh7duc7c7c8d9scbe",
  20.         "userid": "5d4hvh7duc7c7c8d9scbe",
  21.         "name": "name",
  22.         "pic": "url",
  23.     }
  24. ]

将相同用户表与发布的用户ID和已购买用户ID的子数组连接。

请帮助我如何解决这个问题，提前感谢。

英文:

I need to join user collections two times as same user will post product and purchased user details as sub document.

Product Schema:

  1. {
  2.     product_title: String,
  3.     product_desc: String,
  4.     Product_purchased:[
  5.         {
  6.             userid: mongoose.Schema.ObjectId,
  7.             purchased_date: Date
  8.         }]
  9.     posteduserId: mongoose.Schema.ObjectId
  10. }

Users Schema:

  1. {
  2.     _id: userId,
  3.     name: String,
  4.     Pic: String
  5. }

Example document:

  1. [
  2.     {
  3.         "product_title":"title",
  4.         "product_desc":"desc",
  5.         "Product_purchased":[
  6.             {
  7.                 "userid":"5d4hvh7duc7c7c8d9scbe",
  8.                 "name":"name",
  9.                 "Pic":"url",
  10.                 "purchased_date":"Date"
  11.             },
  12.             {
  13.                 "userid":"5d4hvh7duc7c7c8d9scbe",
  14.                 "name":"name",
  15.                 "Pic":"url",
  16.                 "puchased_date":"Date"
  17.             }
  18.         ],
  19.         "posteduserId": "5d4hvh7duc7c7c8d9scbe",
  20.         "userid": "5d4hvh7duc7c7c8d9scbe",
  21.         "name": "name",
  22.         "pic": "url",
  23.     }
  24. ]

Join same user table with posted userid and subarray of purchased userIds.

Please help me how to crack this one, Thanks in advance.

答案1

得分: 1

你需要修复你的产品模式，像这样包含 ref 字段：

  1. const mongoose = require("mongoose");
  3. const ProductSchema = new mongoose.Schema({
  4.   product_title: String,
  5.   product_desc: String,
  6.   Product_purchased: [
  7.     {
  8.       userid: {
  9.         type: mongoose.Schema.ObjectId,
  10.         ref: "User"
  11.       },
  12.       purchased_date: Date
  13.     }
  14.   ],
  15.   posteduserId: {
  16.     type: mongoose.Schema.ObjectId,
  17.     ref: "User"
  18.   }
  19. });
  21. module.exports = mongoose.model("Product", ProductSchema);

我设置用户模式如下：

  1. const mongoose = require("mongoose");
  3. const UserSchema = new mongoose.Schema({
  4.   name: String,
  5.   Pic: String
  6. });
  8. module.exports = mongoose.model("User", UserSchema);

ref 中的 "User" 值必须与用户模型中的模型名称 "User" 匹配。

然后你需要像这样两次填充：

  1. router.get("/products", async (req, res) => {
  2.   const result = await Product.find({})
  3.     .populate("Product_purchased.userid")
  4.     .populate("posteduserId");
  5.   res.send(result);
  6. });

假设你有这3个用户：

  1. {
  2.     "_id": "5e133deb71e32b6a68478ab4",
  3.     "name": "user1 name",
  4.     "Pic": "user1 pic",
  5.     "__v": 0
  6. },
  7. {
  8.     "_id": "5e133df871e32b6a68478ab5",
  9.     "name": "user2 name",
  10.     "Pic": "user2 pic",
  11.     "__v": 0
  12. },
  13. {
  14.     "_id": "5e133e0271e32b6a68478ab6",
  15.     "name": "user3 name",
  16.     "Pic": "user3 pic",
  17.     "__v": 0
  18. }

和这个产品：

  1. {
  2.     "_id": "5e133e9271e32b6a68478ab8",
  3.     "product_title": "product1 title",
  4.     "product_desc": "product1 description",
  5.     "Product_purchased": [
  6.         {
  7.             "purchased_date": "2020-01-06T14:02:14.029Z",
  8.             "_id": "5e133e9271e32b6a68478aba",
  9.             "userid": "5e133df871e32b6a68478ab5"
  10.         },
  11.         {
  12.             "purchased_date": "2020-01-06T14:02:14.029Z",
  13.             "_id": "5e133e9271e32b6a68478ab9",
  14.             "userid": "5e133e0271e32b6a68478ab6"
  15.         }
  16.     ],
  17.     "posteduserId": "5e133deb71e32b6a68478ab4",
  18.     "__v": 0
  19. }

结果将会是：

  1. [
  2.     {
  3.         "_id": "5e133e9271e32b6a68478ab8",
  4.         "product_title": "product1 title",
  5.         "product_desc": "product1 description",
  6.         "Product_purchased": [
  7.             {
  8.                 "purchased_date": "2020-01-06T14:02:14.029Z",
  9.                 "_id": "5e133e9271e32b6a68478aba",
  10.                 "userid": {
  11.                     "_id": "5e133df871e32b6a68478ab5",
  12.                     "name": "user2 name",
  13.                     "Pic": "user2 pic",
  14.                     "__v": 0
  15.                 }
  16.             },
  17.             {
  18.                 "purchased_date": "2020-01-06T14:02:14.029Z",
  19.                 "_id": "5e133e9271e32b6a68478ab9",
  20.                 "userid": {
  21.                     "_id": "5e133e0271e32b6a68478ab6",
  22.                     "name": "user3 name",
  23.                     "Pic": "user3 pic",
  24.                     "__v": 0
  25.                 }
  26.             }
  27.         ],
  28.         "posteduserId": {
  29.             "_id": "5e133deb71e32b6a68478ab4",
  30.             "name": "user1 name",
  31.             "Pic": "user1 pic",
  32.             "__v": 0
  33.         },
  34.         "__v": 0
  35.     }
  36. ]
英文:

First you need to fix your Product schema like this to include the ref field:

  1. const mongoose = require("mongoose");
  3. const ProductSchema = new mongoose.Schema({
  4.   product_title: String,
  5.   product_desc: String,
  6.   Product_purchased: [
  7.     {
  8.       userid: {
  9.         type: mongoose.Schema.ObjectId,
  10.         ref: "User"
  11.       },
  12.       purchased_date: Date
  13.     }
  14.   ],
  15.   posteduserId: {
  16.     type: mongoose.Schema.ObjectId,
  17.     ref: "User"
  18.   }
  19. });
  21. module.exports = mongoose.model("Product", ProductSchema);

I setup user model like this:

  1. const mongoose = require("mongoose");
  3. const UserSchema = new mongoose.Schema({
  4.   name: String,
  5.   Pic: String
  6. });
  8. module.exports = mongoose.model("User", UserSchema);

The ref User value must match the model name User in the user model.

Then you need to populate two times like this:

  1. router.get("/products", async (req, res) => {
  2.   const result = await Product.find({})
  3.     .populate("Product_purchased.userid")
  4.     .populate("posteduserId");
  5.   res.send(result);
  6. });

Let's say you have this 3 users:

  1. {
  2.     "_id": "5e133deb71e32b6a68478ab4",
  3.     "name": "user1 name",
  4.     "Pic": "user1 pic",
  5.     "__v": 0
  6. },
  7. {
  8.     "_id": "5e133df871e32b6a68478ab5",
  9.     "name": "user2 name",
  10.     "Pic": "user2 pic",
  11.     "__v": 0
  12. },
  13. {
  14.     "_id": "5e133e0271e32b6a68478ab6",
  15.     "name": "user3 name",
  16.     "Pic": "user3 pic",
  17.     "__v": 0
  18. }

And this product:

  1. {
  2.     "_id": "5e133e9271e32b6a68478ab8",
  3.     "product_title": "product1 title",
  4.     "product_desc": "product1 description",
  5.     "Product_purchased": [
  6.         {
  7.             "purchased_date": "2020-01-06T14:02:14.029Z",
  8.             "_id": "5e133e9271e32b6a68478aba",
  9.             "userid": "5e133df871e32b6a68478ab5"
  10.         },
  11.         {
  12.             "purchased_date": "2020-01-06T14:02:14.029Z",
  13.             "_id": "5e133e9271e32b6a68478ab9",
  14.             "userid": "5e133e0271e32b6a68478ab6"
  15.         }
  16.     ],
  17.     "posteduserId": "5e133deb71e32b6a68478ab4",
  18.     "__v": 0
  19. }

The result will be:

  1. [
  2.     {
  3.         "_id": "5e133e9271e32b6a68478ab8",
  4.         "product_title": "product1 title",
  5.         "product_desc": "product1 description",
  6.         "Product_purchased": [
  7.             {
  8.                 "purchased_date": "2020-01-06T14:02:14.029Z",
  9.                 "_id": "5e133e9271e32b6a68478aba",
  10.                 "userid": {
  11.                     "_id": "5e133df871e32b6a68478ab5",
  12.                     "name": "user2 name",
  13.                     "Pic": "user2 pic",
  14.                     "__v": 0
  15.                 }
  16.             },
  17.             {
  18.                 "purchased_date": "2020-01-06T14:02:14.029Z",
  19.                 "_id": "5e133e9271e32b6a68478ab9",
  20.                 "userid": {
  21.                     "_id": "5e133e0271e32b6a68478ab6",
  22.                     "name": "user3 name",
  23.                     "Pic": "user3 pic",
  24.                     "__v": 0
  25.                 }
  26.             }
  27.         ],
  28.         "posteduserId": {
  29.             "_id": "5e133deb71e32b6a68478ab4",
  30.             "name": "user1 name",
  31.             "Pic": "user1 pic",
  32.             "__v": 0
  33.         },
  34.         "__v": 0
  35.     }
  36. ]

huangapple
  • 本文由 发表于 2020年1月6日 21:24:15
  • 转载请务必保留本文链接：https://go.coder-hub.com/59612935.html
  • lookup
  • mongodb
  • mongoose
  • node.js
  • subdocument
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