What are the different types of NoSQL databases ? Give some examples

• A Database, which stores data in a format different from relational databases, hence is known as NoSQL Database.
• NoSQL- “not only SQL” which pertains to the fact that either the database can store and manage data using “no SQL” at all.
• It can work in a combination that combines the flexibility of the newer method (NoSQL) with the strength of the traditional relational system (SQL).
• In NoSQL database, there are four types:

1. 1. Key value NoSQL database
   2. Document NoSQL database
   3. Column family NoSQL database
   4. Graph base NoSQL database

Key value NoSQL database :

• In NoSQL database this is the simplest type.
• In this type, the data is stored in the form of key/value pairs.
• The value can be a JSON, BLOB (Binary Large Objects), string, etc.
• It Stores maintain data as pair consisting of an index key and a value.
• The value in a key-value store can be anything: a string, a number, but also an entirely new set of key-value pairs encapsulated in an object.

Document NoSQL database :

• In this, the values are stored in structured documents like XML or JSON, and it is an extension of the simplicity of Key-Value stores.
• In object-oriented software, Document stores make it easy to map Objects.
• It does not support relations and allows us to store complex data in document formats (JSON, XML etc.).
• There is no relational integrity, and Each document in the document store is independent.
• It can be used for all use cases of a KV store database, and also data in each document can be in a different format.

Column family NoSQL database :

• It is developed to store and process very large amounts of data distributed over many machines.
• The columns are arranged by column family, and they point to multiple columns.
• It becomes high performance on aggregation queries like SUM, COUNT, AVG, MIN, etc.

Graph base NoSQL database :

• It is the storage of graph–oriented data structures and is used for specific purposes.
• A graph database is any storage system that provides index-free adjacency.
• No index lookups are necessary, and every node contains a direct pointer to its adjacent element.
• There is no need to define the types of edges and vertices because it usually comes with a flexible data model.