The "case" does matter in MongoDb too!

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 which costs Rs. 27500 and with sales date as 10 June 2016.

I tried to add it as follows:
> db.electronics.insert ( {_id :0006 , category :"TV", brand :"Samsung OLED", sales_date : "10-06-2016", amount :"27500", currency :"INR" })

Now I queried on the collection Electronics again:

> 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" }


Hey, where is the Samsung OLED TV?

Any idea, what happened?

Well, for Mongodb, the collection "electronics" is different from "Electronics".
So, when I added the document by using db.electronics.insert...
MongoDb created a new collection called electronics as can be seen from these two statements:

> show collections
Appliances
Electronics
collection
electronics
system.indexes

The above shows two different collections - Electronics and electronics
Also,
db.electronics.find()
shows:
> db.electronics.find()
{ "_id" : 6, "category" : "TV", "brand" : "Samsung OLED", "sales_date" : "10-06-2016", "amount" : "27500", "currency" : "INR" }
>
>
--

The right way to add would be :

db.Electronics.insert ( {_id :0007 , category :"TV", brand :"Samsung OLED", sales_date : "10-06-2016", amount :"27500", currency :"INR" })

I also add two more entries:

db.Electronics.insert ( {_id :0008 , category :"TV", brand :"Panasonic LED", sales_date : "14-06-2016", amount :"31500", currency :"INR" })
db.Electronics.insert ( {_id :0009 , category :"TV", brand :" OLED", sales_date : "12-06-2016", amount :"15500", currency :"INR" })

And final result is now as expected:


> 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" }
{ "_id" : 7, "category" : "TV", "brand" : "Samsung OLED", "sales_date" : "10-06-2016", "amount" : "27500", "currency" : "INR" }
{ "_id" : 8, "category" : "TV", "brand" : "Panasonic LED", "sales_date" : "14-06-2016", "amount" : "31500", "currency" : "INR" }
{ "_id" : 9, "category" : "TV", "brand" : " OLED", "sales_date" : "12-06-2016", "amount" : "15500", "currency" : "INR" }
>