Sometimes, when working on a particular Technology, we pay a very close attention to some of the features or ways to work on in that technology. However, we tend to ignore other ways. We take a few things for granted, till the day we come across something to the contrary. This is what happened while working with collections and documents in MongoDb. I have this Electronics collection : > db.Electronics.find() { "_id" : ObjectId("55685b94fd45377c7f18bccc"), "category" : "TV", "Sales_Date" : "17-11-2014", "amount" : "32000", "currency" : "INR", "Brand" : "Son y" } { "_id" : "00005", "category" : "Laptop", "Sales_Date" : "05-10-2014", "amount" : "28000", "currency" : "INR", "Brand" : "Acer" } Now I wanted to add a TV of Samsung brand whic...