The concept of relativity in the context of databases refers to the way data is organized and managed. The main idea behind relational databases is the use of tables for storing data and defining relationships between them.

Some Popular Relational Databases

Some popular relational databases include various database management systems, each with its own features. MySQL and PostgreSQL are open-source DBMS (Database Management System), with MySQL being popular for web applications and PostgreSQL offering advanced capabilities.

On the other hand, Oracle Database and Microsoft SQL Server are commercial systems that provide high performance and scalability, making them suitable for large enterprise applications.

The main differences between them lie in licensing and additional features, such as integration with other systems and support for complex functionalities.

Difference from Non-Relational Databases

Relational databases store data in tables with a fixed schema and support SQL for queries. They are well-suited for structured data with clear relationships between them.

Non-relational databases (NoSQL) can use various data storage models (documents, graphs, key-value) and do not require a fixed schema. They are well-suited for unstructured data and large volumes of data that require high scalability and flexibility.

Application of Relational Databases

Relational databases are best used when there is a need to store clearly structured data, where each piece of information is related to another. They are ideal for situations where data integrity is important and accuracy needs to be guaranteed.

Additionally, relational databases become essential when complex queries need to be executed and transactions managed, ensuring the reliability of operations and adherence to all relationships between the data.