The NoSQL Database is a non-relational data management system that does not require a schema. It doesn't require any joins and is simple to scale. A NoSQL database is mostly used for distributed data stores with massive data storage requirements. NoSQL is used in both big data and real-time web apps. Every day, firms like Twitter, Facebook, and Google, for example, amass gigabytes of user data.

A database that is not SQL is referred to as "Not Only SQL" or "Not SQL". NoSQL has become popular, despite the fact that a better term would be "NoREL." In 1998, Carl Strozz coined the term "NoSQL."

Traditional RDBMS employ SQL syntax to store and retrieve data for further processing. A NoSQL database system, on the other hand, refers to a collection of database systems that may hold structured, semi-structured, unstructured, and polymorphic data. In this NoSQL database tutorial, we'll learn about NoSQL using a diagram:

In This, Tutorial you will learn some basic concepts of NoSQL:

• Why NoSQL?
• Brief History of NoSQL Databases
• Features of NoSQL
• Types of NoSQL Databases
• Query Mechanism tools for NoSQL
• What is the CAP Theorem?
• Eventual Consistency
• Advantages of NoSQL

Why NoSQL?

NoSQL databases have gained appeal among Internet behemoths like Google, Facebook, Amazon, and others that deal with large amounts of data. When you utilise RDBMS for large amounts of data, the system response time slows down.

We could “scale up” our systems by updating our existing hardware to overcome this challenge. This procedure is costly.

When the load on the database grows, the option is to disperse it across numerous hosts. Scaling out is the term for this procedure.

Because NoSQL databases aren't relational, they scale out better than relational databases because they're built for online applications.

Brief History Of NoSQL Database:

Although NoSQL is gaining a lot of attention and hype these days, it isn't all that new. I decided to look into the origins of NoSQL and see what I could find. Carlo Strozzi used the term "NoSQL" in 1998 to describe a file-based database that he was working on. It's a relational database, but it doesn't have a SQL interface. As a result, it is not technically a part of the current NoSQL trend. Eric Evans used the term in 2009 to describe the current increase of non-relational databases. For better or worse, it appears that the term has remained. This post does not include all of the projects. For a more comprehensive list, see the essay on assessing the NoSQL landscape.

In 1960’s:

• TRW invented multivalue (or PICK) databases in 1965.
• According to Scott Jones, M[umps] was created in 1966 at Mass General Hospital. It's a programming language with a hierarchical database and B+ tree storage built in.
• In 1966, IBM created IMS, a hierarchical database, in collaboration with Rockwell and Caterpillar for the Apollo space programme.

1970’s:

• InterSystems created the ISM product family, which was followed by the Open M product, which encompassed all M[umps] implementations. Below is a statement from Scott Jones.
• In 1977, M[umps] was recognised as an ANSI standard language.
• Ken Thompson developed DBM, which was published by AT&T in 1979. It's a file-based hash at its core.

1980’s:

DBM's successors spring to life in several ways.

• Atomic transactions are supported by the TDBM.
• The Berkeley version of DBM, NDBM, allowed several databases to be open at the same time.
• SDBM is a clone of DBM that was created primarily for licencing purposes.
• GT.M is the first iteration of a key-value store designed specifically for high-speed transaction processing. In the year 2000, it was become open source.
• BerkeleyDB was established during the transition from 4.3BSD to 4.4BSD at Berkeley. When Netscape requested new functionalities for BerkeleyDB, Sleepycat Software was founded in 1996. BerkeleyDB was later acquired by Oracle, who continues to sell and operate the database.
• Lotus Notes, or more specifically, Lotus Domino, a document database, was first released in 1989 and is presently offered by IBM. It has progressed significantly since its early iterations and is now a complete office and collaboration suite.

1990’s:

DBM's Gnu project clone is GDBM.

• Ericsson created Mnesia as a soft real-time database for usage in telecommunications. It's relational, but it doesn't employ SQL as a query language; instead, Erlang is used.
• InterSystems Caché is a hybrid post-relational database that was first released in 1997. It has object interfaces, SQL, PICK/MultiValue, and direct data structure manipulation. It's a M[umps] implementation, to be sure. For more information on InterSystems' history, see Scott Jones' comment below.
• Metakit was founded in 1997 and is widely considered to be the first document-oriented database. Supports smaller datasets than those now in vogue.

2000-2005:

• This is when the NoSQL train really starts to pick up speed and a lot of things start to happen.
• Neo4j, a graph database, was founded in the year 2000.
• In the year 2000, db4o, an object database for Java and.net, was founded.
• Mikio Hirabayashi's QDBM is a re-implementation of DBM with improved performance.
• Danga created Memcached in 2003 to power Livejournal. Memcached isn't actually a database because it's memory-only, but there will be a memcached version with file storage shortly.
• In 2005, the closed-source Infogrid graph database was released, and in 2008, it was become open-source.
• CouchDB is a document database inspired by Lotus Notes that was founded in 2005. In 2008, the project is transferred to the Apache Foundation.
• The Google BigTable project began in 2004, and the first research paper was published in 2006.

2006-2010:

• JackRabbit began in 2006 as a JSR 170 and 283 implementation.
• Tokyo Cabinet began in 2006 as a successor to (Mikio Hirabayashi's) QDBM.
• In 2007, a research paper on Amazon Dynamo was published.
• MongoDB is a document database that was first released as part of an open source cloud computing stack in 2007 and then as a standalone release in 2009.
• Facebook's open data In 2008, the Cassandra project was launched.
• There is no single point of failure in Project Voldemort because it is a replicated database. It all started in 2008.
• Dynomite is an Erlang-based Dynamo clone.
• Terrastore was founded in 2009 as a scalable and elastic document storage system.
• Redis is a persistent key-value store that was first introduced in 2009.
• Riak In 2009, another dynamo-inspired database was launched.
• HBase is a Hadoop clone of BigTable, whereas Hypertable is another BigTable-like database from 2009.
• In 2009, Vertexdb, a new graph database, was launched.
• Eric Evans of Rackspace, a committer on the Cassandra project, coined the phrase "NoSQL," which means "not only SQL," to describe the explosion of new projects and products.

(Some of these dates should be taken with a grain of salt because pinpointing the exact start dates of projects can be tricky.) Also, not all projects started in the recent few years were considered.)

 We also saw the arrival of NoSQL conferences in 2009 and 2010, such as NoSQL live in Boston in 2010 and the upcoming NoSQL eu in London in April 2010. The NoSQL east conference was also held in Atlanta last year.

• Carlo Strozzi used the name "NoSQL" to describe his open-source relational database in 1998.
• Neo4j, a graph database, is released in the year 2000.
• Google BigTable is launched in 2004.
• CouchDB is launched in 2005.
• The research paper on Amazon Dynamo is published in 2007.
• Facebook releases the Cassandra project to the public in 2008.
• The phrase NoSQL was reintroduced in 2009.