systems.

A database is a collection of organized data stored and accessed electronically. Databases are used to store, organize, and manage data, and are used in a wide variety of applications, such as online stores, libraries, and customer relationship management systems. Some common types of databases include relational databases, which store data in tables with rows and columns, and NoSQL databases, which use a variety of data models, such as documents, graphs, and key-value pairs. There are many database management systems (DBMS) available, ranging from open-source options like MySQL and PostgreSQL, to proprietary systems like Oracle and Microsoft SQL Server.