MySQL is a database management system (DBMS). A database is a structured collection of data. It might be anything from a simple shopping list to a picture gallery, to the vast amounts of information in a corporate network.
To access, manipulate, and process data stored in a database, you need a DBMS. Because computers are very effective at handling large amounts of data, database management plays a central role in computing.
But more than being a DBMS, MySQL is a relational database management system (RDBMS). A relational database stores data in separate tables rather than putting all the data into one large repository. Doing so adds tremendous speed and flexibility. The tables are linked by defined relations making it possible to combine data from several tables upon request.
RDBMS's play a central role in many types of eCommerce and eBusiness solutions. Amazon.com and eBay.com are examples of complex eCommerce solutions that depend on database applications to transact business with their customers and partners.