Mongoose embedded document query returning null - node.js

Question

I have the following schema :
_schema : {
Prize : new Schema({
prizeName : { type : String },
thumbnailImage : [ String ],
detailImage : [ String ],
prizeCategory : [ {type : String, index : true } ],
prizeDescription : { type : String },
prizePrice : { type : Number, required : true }
}),
Game : new Schema ({
roomName : { type : String, required : true },
openTime : { type : Date },
closeTime : { type : Date },
minPlayers : { type : Number },
maxPlayers : { type : Number, required : true },
numberOfPlayers : { type : Number },
winner : { userId : { type : ObjectId, index : true, ref : 'User'} },
prize : [ this.Prize ],
tag : [ { type : String, index : true } ],
status : { type : Number, index : true },
businessType : { type : Number, required : true, index : true },
mallId : { type : ObjectId, ref : 'Mall' },
registeredPlayers : { type : ObjectId, ref : 'User' }
}),
Schedule : new Schema ({
_id : ObjectId,
time : { type : Date, index : true },
game : [ this.Game ]
}),
}
However when I try to query the game embedded document the object is always null. I'm querying like so:
var Schedule = mongoose.model('Schedule', this._schema.Schedule);
Schedule.findById({'game._id' : req.params._id}).exec(function(err,gameDetail){...});
Am I doing anything wrong when I declare the schema and models? I have seen numerous examples where people appear to be doing exactly what I'm trying. Any help would be greatly appreciated! Thanks in advance.

Answer 1

A mongoose Model's findById method is used to find the instance of that Model with the _id that's supplied as the first parameter to the method. So Schedule.findById returns Schedule instances, not individual Game instances. Schedule.findOne({'game._id' : req.params._id}, ... will get you the Schedule instance containing the Game with that id, but if you need to query for Game instances by id, you should be keeping them in a separate collection instead of embedding them in Schedule.

Answer 2

Looking at your code, my first guess is actually that your findById isn't structured quite right.
First, you're using the value req.params._id to get the id. Most of the code examples I have seen, and my code, uses :id in the router (app.get('/schedules/:id')), which would actually mean the ID you're looking for is stored in req.params.id. You'll have to check that in your code.
Secondly, to my understanding, findById is only useful for finding, in this case, a Schedule by that ID. Try using just a normal find.
Last thought: you're missing a closing curly bracket at the end of {'game._id' : req.params._id}.
Hopefully something in that helps. :)