查询 $match 和 $project 重嵌套数据（MongoDB/聚合）

Posted 2023-03-11

【中文标题】查询 $match 和 $project 重嵌套数据（MongoDB/聚合）

【英文标题】：Query $match and $project Heavily Nested Data (MongoDB/Aggregation)

【发布时间】：2021-10-06 02:28:41

【问题描述】：

我需要帮助编写 $project 的单个 business.location.team.member 权限对象的 Mongoose 聚合查询。 MongoDB 关于投影大量嵌套数据的文档不是很好，所以我有点卡住了。

示例集合：

const business = [
    
      b_id: ObjectId("a"),
      locations: [ //can have multiple locations per business
        
           l_id: ObjectId("b"),
           teams: [ //can have multiple teams per location
               
                  t_id: ObjectId("c"),
                  members: [ //can have multiple members per team
                        
                            m_id: ObjectId("d"),
                            permissions:  //each member has a single "permissions" object with different permission objects
                              p1: 
                                a: true,
                                b: false,
                                c: true,
                                d: false,
                              ,
                              p2: 
                                a: true,
                                b: false,
                                c: true,
                                d: false,
                              
                            
                        
                  ]
                
            ]
        
      ]
    ,
  ]

期望的响应：

const permissions = 
  p1: 
    a: true,
    b: false,
    c: true,
    d: false,
  ,
  p2: 
    a: true,
    b: false,
    c: true,
    d: false,
  

路线：

router.post("/", authUser, (req, res) => 
  const _ids = 
    b_id: req.body.b_id, //business _id === "a"
    l_id: req.body.l_id, //locations _id === "b"
    t_id: req.body.t_id, //teams _id === "c"
    m_id: req.body.m_id, //members _id === "d"
  
  Business.aggregate([
    
      $match: 
        b_id: ObjectId(_ids.b_id),
      ,
    ,
    
      $project: 
      //how do I project the perms object from the correct member
      ,
    ,
  ]).then((perms) => 
    console.log(perms);
  );
);

任何帮助将不胜感激，谢谢！

【参考方案1】：

我想通了，它并不漂亮，但它完成了工作。必须有一些迭代的方法来做到这一点？

router.post("/", authUser, (req, res) => 
  const _ids = 
    b_id: req.body.b_id, //business _id === "a"
    l_id: req.body.l_id, //locations _id === "b"
    t_id: req.body.t_id, //teams _id === "c"
    m_id: req.body.m_id, //members _id === "d"
  
  Business.aggregate([
    
      $match: 
        b_id: ObjectId(_ids.b_id),
      ,
    ,
    
      $unwind: "$locations",
    ,
    
      $match: 
        "locations.l_id": ObjectId(_ids.l_id),
      ,
    ,
    
      $unwind: "$locations.teams",
    ,
    
      $match: 
        "locations.teams.t_id": ObjectId(_ids.t_id),
      ,
    ,
    
      $unwind: "$locations.teams.members",
    ,
    
      $match: 
        "locations.teams.members.m_id": ObjectId(_ids.m_id),
      ,
    ,
    
      $project: 
        permissions: ["$locations.teams.members.permissions"],
      ,
    ,
  ]).then((perms) => 
    res.status(200).json(perms[0].permissions[0]);
  );
);