Mongoの1つのパイプラインに少数のコレクションを結合してソートする方法

Question

後ろの関係でソートするユーザーのリストを作成したいと思います。 、

2番目の 'からの要求を受けた'： '送信された要求へ' を

最初に - これを行うために

は、私が順にソートする3つのコレクションのIDを比較する必要があります

第三：「友人、

第四： 'その他'

更新：ユーザーの背後関係を認識 入力

コレクション

db.friends.find({userId: currentUser}); 
    // {"_id" : "qwC7LrtaZtQsShtzT", "userId" : "rbrwhh2AQY8mzmzd3", "friendId" : "4y7pG7p2gcGgm5ayj",} 
db.requests.find({userId: currentUser}); 
    // {"_id" : "PgC7LrtaZtQsShtzT", "userId" : "tHuxnWxFLHvcpRgHb", "requesterId" : "jZagPF7bd4aW8agXb",} 

主なすべてのユーザーとの収集とその情報

db.users.find({userId: currentUser}); 
     // {"_id" : "4y7pG7p2gcGgm5ayj", profile: {name: 'Andrey', second: 'Andrey'}} -> Same person(id) like in 'friends' collection. 
    // {"_id": "tHuxnWxFLHvcpRgHb", profile: {name: 'Erick', second: 'Erick'} -> same person who have receive request. 

そして今、私がする必要が集める 'users' colle以前の2つのコレクション（友人、要求）と一致するスコアを定義します。

私はこの

db.users.aggregate([ 
    // here i tried to compare _id and requesterId to fetch all who received request from me: 
    {$lookup: {from: 'requests', localField: "_id", foreignField: "requesterId", as: "sentRequest"}}, 
    {$unwind: '$sentRequest'}, 
    {$project: {_id: '$sentRequest.userId', profile: 1, count: {$add: [2]}}}, 
    // And here I tried to get all friends 
    {$lookup: {from: 'requests', localField: "_id", foreignField: "friendId", as: "friends"}}, 
    {$unwind: '$friends'}, 
    {$project: {_id: '$friends.userId', profile: '$profile', count: {$add: [3]}}} 

]); 

のように実行しようとしましたが、結果には、私は最後の部分だけ（友人）を取得し、別の問題

[ { _id: 'rbrwhh2AQY8mzmzd3', //this field is responds to person which I looking for 
profile: //But profile data is given from .users and its not respont to person with given id 
    { firstName: 'Andrey', 
    lastName: 'Andrey', 
    userImg: '/img/user.jpg', 
    userDescription: null }, 
    count: 3 } ] 

UPDATE

と期待される結果

//Given: 3 collections 
db.users -> provide all additional info about all users 
db.requests -> groups IDs of two users 'requester' and 'receiver' 
db.friends -> groups IDs of two users 'friend' and 'user', document has pair where value are swapped (but it's not important in this task); 

//Need to combine all of this three collections in one queue, to sort users by their relationships between them, in kind of this list: 
// 1 - Requests; 2 - Friends; 3 - Other users 


// Expected result: 
[ 
    // I've got request From: 
    { "_id": "tHuxnWxFLHvcpRgHb", // _id must be equal to user who sent request and _id from db.users 
     "profile": // this value used from db.users 
     { 
      "firstName": "Ana", 
      "lastName": "de Armas", 
      "userImg": "/img/user.jpg", 
      "userDescription": null 
     }, 
      "weight": 4 // given value to make sorting then 
    }, 
    // I sent request To: 
    { "_id": "4y7pG7p2gcGgm5ayj", 
     "profile": 
     { 
      "firstName": "John", 
      "lastName": "Bonjovi", 
      "userImg": "/img/user.jpg", 
      "userDescription": null 
     }, 
      "weight": 3 
    }, 
    // My friend: 
    { "_id": "jZagPF7bd4aW8agXb", 
     "profile": 
     { 
      "firstName": "Jessica", 
      "lastName": "Alba", 
      "userImg": "/img/user.jpg", 
      "userDescription": null 
     }, 
      "weight": 2 
    }, 
    // Unknown user: 
    { "_id": "DdX8sPuAoZqKpa6nH", 
     "profile": 
     { 
      "firstName": "Sheldon", 
      "lastName": "Cooper", 
      "userImg": "/img/user.jpg", 
      "userDescription": null 
     }, 
      "weight": 1 
    } 
] 

私は$検索と集約を使用しようとした - が、その3つのコレクションでは動作しません。

結果では、私は新しい結合されたコレクションの新しいフィールドを設定できるキューを返す必要があります - 体重。このフィールドで並べ替えることができます。

Answer 1

最新モンゴ3.4バージョンには、複数の集約パイプライン全体で同じデータを処理するために使用$facetを作成し、すべてのaggregrationからの単一出力に結果を結合します。

db.users.aggregate([ 
    { "$match": { "_id":1} }, 
    { 
     "$facet": { 
      "Received": [ 
       {$lookup: {from: 'requests', localField: "_id", foreignField: "userId", as: "receivedRequest"}}, 
       {$unwind: '$receivedRequest'}, 
       {$lookup: {from: 'users', localField: "receivedRequest.requesterId", foreignField: "_id", as: "receivedUser"}}, 
       {$project: {_id: '$receivedRequest.requesterId', profile: '$receivedUser.profile', weight: {$add: [4]}}} 
      ], 
      "Sent": [ 
       {$lookup: {from: 'requests', localField: "_id", foreignField: "requesterId", as: "sentRequest"}}, 
       {$unwind: '$sentRequest'}, 
       {$lookup: {from: 'users', localField: "sentRequest.userId", foreignField: "_id", as: "sendUser"}}, 
       {$project: {_id: '$sentRequest.userId', profile: '$sendUser.profile', weight: {$add: [3]}}} 
      ], 
      "Friends": [ 
       {$lookup: {from: 'friends', localField: "_id", foreignField: "userId", as: "friends"}}, 
       {$unwind: '$friends'}, 
       {$lookup: {from: 'users', localField: "friends.friendId", foreignField: "_id", as: "friendUser"}}, 
       {$project: {_id: '$friends.friendId', profile: '$friendUser.profile', weight: {$add: [2]}}} 
      ], 
      "Others": [ 
       {$lookup: {from: 'friends', localField: "_id", foreignField: "friendId", as: "others"}}, 
       {$unwind: '$others'}, 
       {$lookup: {from: 'users', localField: "others.userId", foreignField: "_id", as: "other"}}, 
       {$project: {_id: '$others.userId', profile: '$other.profile', weight: {$add: [1]}}} 
      ] 
     } 
    } 
]).pretty() 

サンプル出力：

{ 
     "Received" : [ 
       { 
         "_id" : 3, 
         "profile" : [ 
           { 
             "name" : "John" 
           } 
         ], 
         "weight" : 4 
       } 
     ], 
     "Sent" : [ 
       { 
         "_id" : 4, 
         "profile" : [ 
           { 
             "name" : "Jessica" 
           } 
         ], 
         "weight" : 3 
       } 
     ], 
     "Friends" : [ 
       { 
         "_id" : 2, 
         "profile" : [ 
           { 
             "name" : "Ana" 
           } 
         ], 
         "weight" : 2 
       } 
     ], 
     "Others" : [ 
       { 
         "_id" : 5, 
         "profile" : [ 
           { 
             "name" : "Sheldon" 
           } 
         ], 
         "weight" : 1 
       } 
     ] 
}