Final answer:
The external layer of the ANSI/SPARC model provides logical data independence, allowing for changes in the conceptual schema without affecting external views or applications.
Step-by-step explanation:
The external layer of the ANSI/SPARC model provides logical data independence, which is the capability to change the conceptual schema without having to change the external schemas or application programs. It allows flexibility in the way that data is viewed by different users according to their needs, without altering the underlying database structure.
This is opposed to physical data independence, which pertains to the internal layer and refers to the ability to change the internal schema without having to change the conceptual schema or any external schemas. Logical data independence is essential for maintaining user interfaces even as the underlying database structure evolves.
The external layer of the ANSI/SPARC model provides logical data independence and encapsulation. Logical data independence refers to the ability to make changes to the logical structure of the database without affecting the external applications or programs that use it.
Encapsulation refers to the process of hiding the internal details and complexities of the database, providing a simplified and consistent interface to the users.