How PHP and MySQL Work Together in WordPress
WordPress uses a PHP/MySQL platform, which provides everything you need to create your own site and publish your own content dynamically, without knowing how to program those pages. In short, all your content is stored in a MySQL database in your hosting account.
PHP is a server-side scripting language for creating dynamic web pages. When a visitor opens a page built in PHP, the server processes the PHP commands and then sends the results to the visitor’s browser.
MySQL is an open-source relational database management system (RDBMS) that uses Structured Query Language (SQL), the most popular language for adding, accessing, and processing data in a database. If all that sounds like Greek to you, just think of MySQL as a big filing cabinet where all the content on your site is stored.
Every time visitors go to your site to read your content, they make a request that’s sent to a host server. The PHP programming language receives that request, makes a call to the MySQL database, obtains the requested information from the database, and then presents the requested information to your visitors through their web browsers.
Here content refers to the data stored in the MySQL database — that is, your blog posts, pages, comments, links, and options that you set up on the WordPress Dashboard. However, the theme (or design) you choose to use for your site — whether it’s the default theme, one you create, or one you have custom-designed — isn’t part of the content in this case.
Theme files are part of the file system and aren’t stored in the database. So creating and keeping a backup of any theme files that you’re currently using are good ideas.
It’s a good idea to back up your WordPress website with the BackupBuddy plugin.