What is a Database?

A database is a collection of data stored in a computer. A Database Management System (DBMS) is a software package that efficiently manages databases and lets one or more people use or modify the contents of the database. The main function of the DBMS is to manage the internal representation of the data in a form optimized for computer access, and to respond to requests from users to access or modify the data. The DBMS translates these requests into database commands that it then performs on the data.

One of the most common and powerful languages for accessing databases is SQL. SQL (Structured Query Language) commands perform actions on the database. There are two types of SQL commands: DDL (Data Definition Language) commands, which are used to define the structure of the data, and DML (Data Manipulation Language) commands, which are used to manipulate the data itself. The data is organized into tables in the database. Tables contain rows (sometimes called records) and columns (sometimes called fields). The structure of the table and its columns is defined by DDL commands. The commands to insert or update values in the rows of the table are DML commands.