Three basic structures in WordPress interact to create your web pages: the core, the theme, and the database.
- The CORE is the set of files that make up WordPress and perform the tasks of storing, retrieving, and assembling content.
- The DATABASE is where your content is stored.
- The THEME is made up of template files that provide instructions to the core about what to retrieve from the database and how to assemble it.
The web address you type into a browser window goes to the WordPress core, which then checks with the database to determine which template file to look for in the theme. The core then reads the template file and follows the instructions about what chucks of content to retrieve. Having found the content, the core then assembles the chunks of information according to the template’s instructions and you see the result as the HTML page in your web browser. And all this happens in a matter of seconds!
Excerpt from “WordPress 24-Hour Trainer”