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MongoDB: How to find by subdocument ID?

I am trying to simulate a concept gameswhere teamsof playerscompete with each other in MongoDB.

I have two collections: playersand games.

Here's what the document looks like in games.

{
    "_id": { "$oid": "1" },
    "teams": [
        {
            "players": [
                {
                    "player": { "$oid": "2" },
                    "score": 500,
                },
                {
                    "player": { "$oid": "3" },
                    "score": 550,
                }
            ]
        },
        {
            "players": [
                {
                    "player": { "$oid": "4" },
                    "score": 500,
                },
                {
                    "player": { "$oid": "5" },
                    "score": 550,
                }
            ]
        }
    ]
}

Here's the problem: given the ID of the player, I want to find all the games in which this player participated.

What I tried:

db.games.find( { "teams.players.player._id": "2" } )

However, this does not return anything.

By the way, I am using Mongoose with the following scheme:

playerSchema = Schema
    player: { type: Schema.ObjectId, ref: 'Player' }
    score: { type: Number }

teamSchema = Schema
    players: [ playerSchema ]

gameSchema = Schema
    teams: [ teamSchema ]

with the following CoffeeScript request:

Game.find 'teams.players.player._id': playerId

which does not return results for any player identifier.

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2 answers

In your document:

"players": [
            {
                "player": { "$oid": "4" },
                "score": 500,
            },
            {
                "player": { "$oid": "5" },
                "score": 550,
            }
        ]

player players BSON (.. ObjectId("4e208e070347a90001000008")), , :

db.games.find( { "teams.players.player": ObjectId("2") } )

, _id - mongo, , ( _id).

+8

, . , Mongo , . - .

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// Schemas
var playerSchema = new Schema({
    name: {type: String, index: true, unique: true},
    games: {type: [Schema.ObjectId], ref: 'Game'}
});

var gameSchema = new Schema({
    homeTeam: [{player: {name: String}, score: Number}]
    awayTeam: [{player: {name: String}, score: Number}]
});

// Models
var Player = mongoose.model('Player', playerSchema);
var Team = mongoose.model('Team', teamSchema);
var Game = mongoose.model('Game', gameSchema);

// Middleware
gameSchema.post('save', function (game) {
    var addMatchToPlayer = function(name) {
        Player.findOne({name: name}, function(err, player) {
            if (!err && player && player.games.indexOf(game._id) === -1) {
                player.games.push(game._id);
                player.save();
            }
        });
    }
    for (var i = 0; i < game.homeTeam.length; i++) {
        addMatchToPlayer(game.homeTeam[i].name);
    }
    for (var i = 0; i < game.awayTeam.length; i++) {
        addMatchToPlayer(game.awayTeam[i].name);
    }
});

// Queries
Player.findOne({name: 'Roel van Uden'}).populate('games').exec(function (err, player) {
});
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