Databases - The Basics

A database is a structured set of data. It is an organized collection of information that can easily be accessed, managed, and updated. Databases can be electronic, like a spreadsheet or a customer relationship management system, or physical, like a phone book.

Databases are used in many different situations and can handle amounts of information ranging from a few dozen records to millions or even billions. They can manage anything from a list of contacts in your phone to all the transactions processed by a major credit card company. They can also contain various types of information, such as numerical data, text, images, audio, and video.

In computer science, databases are often classified according to their relational model. The most popular type of database system is the Relational Database Management System (RDBMS), which uses Structured Query Language (SQL) to manage the database. Examples of RDBMS are Oracle, MySQL, and PostgreSQL. These systems store data in tables, and the relationships between the data are also stored in tables.

There are also non-relational databases, often called NoSQL databases, which can be more flexible because they store data in a variety of ways, not just tables. Examples of NoSQL databases include MongoDB, Cassandra, and Redis.