MongoDB is a non-relational database (often known as No-SQL). It is an open-source document database that provides high performance, high availability, and automatic scaling.

In simple words, you can say that — Mongo DB is a document-oriented database. It is an open source product, developed and supported by a company named 10gen.

Why MongoDB?

Because sometimes applications cannot have predefined schema, so it can’t be represented in terms of RDBMS.

Another reason, well there is less support for the scaling. Eventually, you will need to buy Teradata or MySQL’s database system that supports scaling which are very expensive.

And the amount of time that database admin spend to design schema for database is enormous. The design of the database can take years in some application to be developed.

So eventually everyone in IT thought that we need a new solution that takes less time and has less restriction. So they came up with No-SQL system. Now there are many No-SQL system some are good for certain things while others are good at other things.

Day1

1st May 2021

🎯We store data in a file and the file is stored in a folder and the folder is stored in a hard disk to make it persistent.

WHAT IS DATA MODEL?

🎯Data model is the way to organise data in any database to enhance performance of the system and also the space complexity.

WHAT IS SQL?

🎯SQL stands for Structured Query Language. In SQL, there is presence of schema which means the number of fields are fixed and we cannot dynamically change them. NoSQL stands for not SQL. We can change fields on the fly in a NoSQL database as per our requirement.

WHAT IS MS-EXCEL?

🎯MS Excel is a software from Microsoft that helps us to store data in the form of spreadsheets in rows and columns.

🎯By the help of the Insert operation, we can add documents to the collection of our NoSQL database.

🎯In Schemaless DB, the fields are not fixed and any field can be added anytime on the fly as per our requirement, this gives us the flexibility to store data.

🎯A database in which each record is treated as a complete document is known as a document oriented database. Mongo DB is a type of document oriented database.

🎯Indexes are a fast way to retrieve/search data from a document in a database as it improves input/output performance.

🎯Primary key is a unique key assigned to every document in a NoSQL database.

Day2

8 May 2021

👉 What is indexing in MongoDB ?

1.Indexing- Indexes support the efficient resolution of queries. Without indexes, MongoDB must scan every document of a collection to select those documents that match the query statement.

👉 What is sharding in MongoDB ?

Sharding is the process of grouping the data and splitting this data to multiple slave nodes also called as replica instances.

👉 What is Replica set in MongoDB ?

By default in MongoDB find() scans the entire collection known as collection scanning(COLLSCAN) and if we use indexing then that scanning is IXSCAN.

👉 What is IXSCAN and COLLSCAN in MongoDB ?

1.IXSCAN is index scanning.

2.COLLSCAN is collection scanning : scans all the document present in a collection

👉 What is Compound Indexing in MongoDB ?

When we create an index of two or more items at once then it is called compound indexing.

👉 What is MongoDB aggregation pipeline ?

An aggregation pipeline is a framework provided by MongoDB by which we can create a set of queries or pipelines in the form of various stages.

👉 What is Mongo Router Program in MongoDB ?

Mongo Router program in MongoDB is actually a router kind of a program present in the master node of the cluster.It holds the metadata of the data present in each slave node. So when there is a client query for the data it redirects the query to that particular slave node that contains the data.

👉 What is Referencing Model in MongoDB ?

Referencing model is a kind of architectural design for storing the data into multiple documents.

👉 What is the use of MongoDB Atlas ?

MongoDB Atlas is a cloud platform provided by MongoDB where we can create our cluster.

👉 What are clusters in MongoDB ?

Cluster is an architectural design of master and slave nodes/target nodes to prevent the problem of single point of failure.