Summary
Drupal harnesses relational database principles to help structure content through its Entity subsystem. This ubiquitous system impacts content and configuration and integrates with other features such as Views. Effective structured content follows conventions borrowed from databases, such as atomic fields and normalization. Entities are highly extensible through various settings, capabilities tied to fields, and multilingual features. Given the foundational nature of entities, it is extremely important to understand the system and how to leverage it properly throughout Drupal.
The next chapter will explore users, roles, and permissions, which allow for a tailored experience for different administrative purposes.