MySQL Explained: The Database Behind Much of the Web
Introduction When you learned SQL (the SQL post), you learned a language — but a language needs a database to run in. MySQL, first released in 1995 and now owned by Oracle, is the most widely used open-source relational database in the world: it stores WordPress sites, runs parts of Facebook and Wikipedia, and is the default database in the classic LAMP stack (Linux, Apache, MySQL, PHP — three of which this blog has already covered). If you know SQL, learning MySQL is mostly learning how that language lives in a real system. Tables, rows, and the engine underneath MySQL organises data the relational way: tables with columns and rows, linked by keys. A users table might hold an id, a name, and an email; an orders table holds an order id, a user id pointing back to users, and a total — and a JOIN (the SQL post's joins) reassembles them on demand. Two practical things distinguish MySQL from SQL-the-language. First, storage engines: InnoDB (the default) gives you transactions and fo...