Understanding the WordPress database
Typical full stack web development frameworks don't come with a preplanned database structure. Instead, these frameworks focus on the core foundation of an application while allowing the developers to focus on application-specific features. On the other hand, WordPress provides a preplanned database structure with a fixed set of tables. WordPress is built to function as a content management system and hence it can be classified as a product rather than a pure development framework. A WordPress core database is designed to power the generic functionalities of a CMS. So, it's our responsibility to use our skills to make it work as an application development framework.
Our WordPress database is intended to work with MySQL and hence we need to have a MySQL database set up before installing WordPress. On successful installation, WordPress will create 11 database tables to cater to core functionality with the default MySQL table engine.
Note
MyISAM was used as the default MySQL table engine prior to Version 5.5 and has been changed to InnoDB from Version 5.5 onwards.
WordPress core features will always be limited to these 11 tables, and it's quite surprising to see the flexibility of building a wide range of applications with such a limited number of tables. Both WordPress and framework developers need to have a thorough understanding of the existing tables in order to associate them in web applications.