What is the role of data definition in a DBMS?

The role of data definition in a Database Management System (DBMS) is pivotal because it pertains specifically to how the structure of the database is defined and maintained. This includes the creation, modification, and organization of database schema, which encompasses tables, fields, data types, relationships, constraints, and indexes.

By focusing on this structure, data definition ensures that data is stored in a way that facilitates efficient access, integrity, and consistency over time. This is essential for proper data management, as it determines how data elements interact and relate to one another within the database framework.

While data retrieval, user access management, and storage of application data files are significant functions of a DBMS, they are not the primary focus of data definition. Data retrieval is concerned with querying the data according to the established structures. User access and security management involve controlling who can see or manipulate data, and managing application data files focuses on where the actual data is physically stored, rather than the structural rules governing the data itself. Thus, the correct understanding of data definition is crucial for anyone working with or studying database systems.