Difference Between SQL and NoSQL

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Introduction

There are two types of data structures present i.e relational database and non-relational database. The main difference between SQL and NoSQL is SQL is a relational database language(RDBMS)  whereas NoSQL is a non-relational database language or distributed. This article mainly explains the differences between SQL and NoSQL. The factors on which they are different are discussed in the below article:

Type:

SQL is a relational database (RDBMS) compared to NoSQL is a non-relational or distributed database.

Language:

SQL (Structured Query Language) is one of the most versatile and widely used database languages for complex queries. SQL uses already-defined schemas for the structure of the data. For working on such kinds of databases we have to use the pre-defined schemas present. This is considered to be a disadvantage because it requires a lot of preparation to change the structure because it is considered to be difficult and disturbs the whole database. Compartelivy, a NoSQL is a dynamic schema that has unstructured data. Data in NoSQL can be stored in many ways like document-oriented, column-oriented, graph-oriented, and key-value pairs. NoSQL doesn't have any pre-defined schema to be followed to write complex queries.

Scalability:

SQL is considered to be vertically scalable which means that it can increase the load on one single server by expanding the size of RAM, and increasing CPU time and SSD. Comparatively, NoSQL is horizontally scalable which means that it can increase or decrease the number of servers according to  the needs of the user. Therefore NoSQL can become larger and more powerful compared to SQL.

Properties:

SQL follows the ACID property (Atomicity, Consistency, Isolation, Durability) on the other hand NoSQL follows the  Brewers CAP theorem  (Consistency, Availability, and Partition tolerance).

For a better understanding of what are the differences between SQL and NoSQL, the below table is used:

SQL

NoSQL

SQL is a relational database (RDBMS)

NoSQL is used for a non-relational database.

SQL uses already-defined schemas and they cannot be changed. They have predefined schemas which cannot be modified.

NoSQL doesn't have any pre-defined schemas and they can be changed.

This data is stored in form of tables, and entity relationship models

This data is stored in form of graph-oriented, column-oriented, document-oriented, etc.

SQL is considered to be horizontally scalable.

NoSQL is vertically scalable.

SQL follows ACID (Atomicity, Consistency, Isolation, Durability)  properties.

NoSQL doesn't follow ACID properties instead it follows the Brewers CAP theorem  (Consistency, Availability, and Partition tolerance).  


SQL is not considered to be preferred for hierarchical data storage.

NoSQL is considered to be suitable for hierarchical data storage.

Examples of SQL languages are MySQL, PostgreSQL, Oracle,  etc:


Examples of NoSQL languages are Django, GraphQL, Cassandra, etc

Conclusion:

Key differences between SQL and NoSQL are discussed in the above article.

SQL is used for Relational databases whereas NoSQL is used for non-relational databases. Examples of SQL languages are MySQL, Oracle, etc. Examples of NoSQL Django, GraphQL, etc.