Mongoose - reference an embedded id in the parent document - node.js

Question

I have this simple schema so far:
var room = new Schema(
{
name: { type: String, default: null, trim: true }
});
var event = new Schema({
name: { type: String, default: null, trim: true },
startDate: Date,
endDate: Date,
logo: { type: Boolean, default: false },
public: { type: Boolean, default: false },
rooms: [room]
sessions: [
{
title: { type: String, default: null, trim: true },
description: { type: String, default: null, trim: true },
date: Date,
start: Number,
end: Number,
room: { type: Schema.Types.ObjectId, ref: 'room' }
}
]
});
I know how to reference another collection but how do I reference an embedded id in the parent document?
I know this schema is not right because even If I delete a room, the room reference is not removed from a session where it is referenced.
Thanks in advance!

Answer 1

You could create a reference to the event in room schema.Then use the schema.pre middleware to remove the sessions.room value whenever you do a remove on the main parent room.(make sure you remove the eventid from main room schema as well).Also refer Removing many to many reference in Mongoose
var room = new Schema({
name: {
type: String,
default: null,
trim: true
},
eventid: {
type: Schema.Types.ObjectId, //Set reference to event here.
ref: 'event'
}
});
room.pre('remove', function(next) {//event is the schema name.
this.model('event').update({; //this will have all the models,select the event
sessions.room: this._id//will have the room id thats being deleted
}, {
$pull: {
sessions.room: this._id//removes that array from the event.sessions.room
}
}, {
multi: true
},
next();//continues and completes the room.remove.
);
});