Which component is NOT part of a database system?

The correct answer is the component that does not belong as an integral part of a database system. A database management system (DBMS) is essential as it serves as the software that manages databases, providing the necessary tools for data storage, manipulation, and retrieval. The data processing language is also a vital component, as it refers to the languages used to interact with the database, such as SQL, enabling users to execute queries and manage the data.

The database itself is the collection of organized information stored digitally, making it another fundamental aspect of a database system. In contrast, user interface design, while important for user interaction with software applications, is not a necessary component of the database system itself. Instead, it is a separate aspect focused on the experience and ease of use for individuals working with the database through applications or tools, rather than being a core part of how the database and its management system operate. Therefore, this distinction makes user interface design the component that does not fit as a fundamental part of a database system.