core

MySQL

MySQL is an open-source relational database management system that stores and retrieves structured data using SQL (Structured Query Language). Every WordPress site runs on MySQL — or its drop-in...

MySQL

MySQL is an open-source relational database management system that stores and retrieves structured data using SQL (Structured Query Language). Every WordPress site runs on MySQL — or its drop-in replacement, MariaDB — as the engine that holds your posts, pages, comments, users, plugin settings, and theme options.

Answer capsule: MySQL is the database layer of WordPress. When you publish a post, WordPress writes it to a MySQL database. When a visitor loads that page, WordPress queries the database and retrieves it. Without MySQL, WordPress has no persistent storage — it cannot function.

What does MySQL store in a WordPress site?

Every piece of content and configuration on your WordPress site lives in a MySQL database, typically named with a wp_ table prefix. The default installation creates 12 tables including wp_posts, wp_options, and wp_users. Plugins add their own tables on activation — on a site with 30 active plugins, we commonly see 60–80 tables total.

When will you encounter MySQL as a site owner?

Most WordPress users interact with MySQL indirectly, through tools. You encounter it directly in three situations:

  • Setting up WordPress: The installer asks for a database name, username, password, and host — all MySQL credentials.
  • Migrating a site: Moving WordPress to a new host means exporting the MySQL database as a .sql file and importing it on the destination server.
  • Debugging database errors: The “Error establishing a database connection” message means WordPress cannot reach MySQL — usually a wrong credential or a crashed MySQL service.

We see this error on client sites most often after a host-side MySQL restart that doesn’t auto-reconnect; a quick cache flush or wp-config.php credential check resolves it 90% of the time.

MySQL vs MariaDB: does it matter for WordPress?

MariaDB is a community fork of MySQL, created in 2009 after Oracle acquired MySQL. As of 2026, most shared hosts — including SiteGround and Hostinger — run MariaDB by default. WordPress treats both identically; the WordPress minimum requirements page lists “MySQL 8.0 or MariaDB 10.5 or greater” as the current standard. For practical WordPress use, the distinction is invisible.

A basic example

When you save a post, WordPress runs an INSERT query like this behind the scenes:

INSERT INTO wp_posts (post_title, post_content, post_status)
VALUES ('My Page Title', 'Page content here', 'publish');

You never write this query yourself — WordPress handles it. But understanding that it happens explains why database performance directly affects page load time. A slow MySQL server means slow queries, which means slow pages regardless of your CDN or caching plugin.

Additional reading:

Back to Glossary