What are the different types of databases?

Relational Database

A relational database, also known as a Relational Database Management System (RDBMS) or SQL (Structure Query Language) database, is a collection of data items with pre-established relationships between them. Data items in relational databases are organized as a series of tables with columns and rows. A field keeps the actual value of an attribute, and each column in a table holds a specific type of data. The table's rows stand for a group of connected values for a single object or entity. A primary key, which serves as a distinctive identifier for every row in a table, can be used to link rows from different tables together.