quick-mongodb-snippets.md

Inserting new attribute to an existing document in MongoDB

Say first I have the below user collection with only one document, and I can see that by running db.users.find().pretty() . Now I want to add another attribute or property to this document named 'port' and given this attribute is of Schema.Types.ObjectId type in user collection, I have to add the corresponding port's _id field to it as its value. So lets say that field is - "5bd983e4a18ceecf4bba3c48"

{
	"_id" : ObjectId("5bd983e4a18ceecf4bba3c48"),
	"username" : "p@gmail.com",
	"password" : "$2a$10$HyXCD5.4U/0CvZHq9SDQ0uxD12BQ46yVAHu18lRRVEQZB3uyHXgy.",
	"__v" : 0
}

So the command to add port value is

db.users.update({'_id' : ObjectId("5bd983e4a18ceecf4bba3c48")},
                      {'$set' : {'port' : "5bdaadc9ebae106aaa8ca247" }})