Mongoose.model vs Connection.model vs Model.model

Question

I am bit confused with usage of models in mongoosejs

Models can be created using mongoose in these ways

Using Mongoose

var mongoose = require('mongoose');
var Actor = mongoose.model('Actor', new Schema({ name: String }));

Using Connection

var mongoose = require('mongoose');
var db = mongoose.createConnection(..);
db.model('Venue', new Schema(..));
var Ticket = db.model('Ticket', new Schema(..));
var Venue = db.model('Venue');

Using existing Model instance

var doc = new Tank;
doc.model('User').findById(id, callback);

Now what is the difference between model returned by Mongoose.model , Connection.model and Model.model. and when to use what , what is the recommended way to create/fetch model ?

Answer 1

1. mongoose.model ties the defined model to the default connection that was created by calling mongoose.connect.
2. db.model ties the model to the connection that was created by calling var db = mongoose.createConnection.
3. doc.model looks up another model by name using the connection that doc's model is tied to.

All three can be sensibly used in the same program; which one to use just depends on the situation.