为啥我的 Mongoose 填充请求不起作用？

Posted 2023-03-10

【中文标题】为啥我的 Mongoose 填充请求不起作用？

【英文标题】：Why my Mongoose populate request does not work?为什么我的 Mongoose 填充请求不起作用？

【发布时间】：2021-12-20 13:51:18

【问题描述】：

在我的数据库中，我收集了 totalpoints 和以下示例文档：

  "_id": 
    "playerId": "113069",
    "tournamentId": "197831"
  ,
  "playerName": "xyz",
  "pointsTotal": 0,
  "__v": 0

对于名为 teams 的其他集合之一，我定义了以下架构：

const teamsSchema = new Schema(
    _id: 
        teamName: String,
        tournamentId: String
    ,
    tournamentName: String,
    player1: 
        type:  Schema.Types.ObjectId,
        ref: 'PointTotal',
    
)

我在 MongoDB 的团队收藏中得到的是这个文档：

    "_id": 
        "teamName": "BILALATI6449",
        "tournamentId": "197831"
    ,
    "tournamentName": "Amanora Cricket Championship 2021",
    "player1": 
        "playerId": "113069",
        "tournamentId": "197831"
    ,
  "_v": 0

但是，当我执行以下代码时：

const doc = await Team.findOne(
    "_id.teamName": "BILALATI6449",
    "_id.tournamentId": "197831"
).populate("player1")
console.log(doc)

以下结果打印到控制台，.populate 不工作：

  _id:  teamName: 'BILALATI6449', tournamentId: '197831' ,
  tournamentName: 'Amanora Cricket Championship 2021',
  __v: 0

这是完整的文档样本表单团队集合：

  "_id": 
    "teamName": "BILALATI6449",
    "tournamentId": "197831"
  ,
  "tournamentName": "Amanora Cricket Championship 2021",
  "player1": 
    "playerId": "2331078",
    "tournamentId": "197831"
  ,
  "player2": 
    "playerId": "196713",
    "tournamentId": "197831"
  ,
  "player3": 
    "playerId": "113069",
    "tournamentId": "197831"
  ,
  "player4": 
    "playerId": "249044",
    "tournamentId": "197831"
  ,
  "player5": 
    "playerId": "113129",
    "tournamentId": "197831"
  ,
  "player6": 
    "playerId": "181056",
    "tournamentId": "197831"
  ,
  "player7": 
    "playerId": "658022",
    "tournamentId": "197831"
  ,
  "player8": 
    "playerId": "182623",
    "tournamentId": "197831"
  ,
  "player9": 
    "playerId": "249047",
    "tournamentId": "197831"
  ,
  "player10": 
    "playerId": "658053",
    "tournamentId": "197831"
  ,
  "player11": 
    "playerId": "658057",
    "tournamentId": "197831"
  ,
  "__v": 0

【问题讨论】：

如果你想我可以用$lookup回答这个问题

@mohammadNaimi 是的，请回答。

【参考方案1】：

在团队集合中使用聚合

db.team.aggregate([
  
    "$match": 
      "_id.teamName": "BILALATI6449",
      "_id.tournamentId": "197831"
    
  ,
  
    "$lookup": 
      "from": "totalpoints",
      "localField": "player1.playerId",
      "foreignField": "_id.playerId",
      "as": "player1"
    
  
])

https://mongoplayground.net/p/nGJSZ6kJMIc

如果为您提供具有多个玩家编号的新样本数据，请使用此

db.team.aggregate([
  
    "$match": 
      "_id.teamName": "BILALATI6449",
      "_id.tournamentId": "197831"
    
  ,
  
    "$addFields": 
      "newField": 
        "$filter": 
          "input": 
            "$objectToArray": "$$ROOT"
          ,
          "as": "p",
          "cond": 
            "$regexMatch": 
              "input": "$$p.k",
              "regex": ".*player*."
            
          
        
      
    
  ,
  
    "$lookup": 
      "from": "totalpoints",
      "localField": "newField.v.playerId",
      "foreignField": "_id.playerId",
      "as": "players"
    
  ,
  
    "$project": 
      _id: 1,
      tournamentName: 1,
      players: 1
    
  
])

https://mongoplayground.net/p/ctGybQzGrW7

【讨论】：

我可以将它与 findOne() mongoose 方法一起使用吗？

不，这是不同的方法await Team.aggregate 像这样

我在同一个文档中还有 10 多个播放器作为单独的对象，每个播放器指向 pointtotals 集合中的不同文档。我该如何管理它们？

提供样本完整数据

我已包含完整的示例文档。