CPS 510 MIDTERM EXAMINATION TEST FINAL PAPER FULL SOLUTION 2026 GRADED A+.

CPS 510 MIDTERM EXAMINATION TEST
FINAL PAPER FULL SOLUTION 2026 GRADED
A+.



⫸ What is a database instance? Answer: The actual data stored in the
database at a specific time.


⫸ What are the three levels in the ANSI/SPARC architecture?
Answer: External, Conceptual, and Internal levels.


⫸ What does the external level represent? Answer: User-specific or
application-specific views of the data.


⫸ What does the conceptual level represent? Answer: The
community logical model describing all data and relationships for the
enterprise.


⫸ What does the internal level represent? Answer: Physical storage
structures and access paths on disk.


⫸ What is a mapping in the three-level architecture? Answer: A
translation mechanism between schema levels that maintains
consistency.

, ⫸ What is data independence? Answer: The ability to change schema
at one level without affecting higher levels.


⫸ What are the two kinds of data independence? Answer: Logical
(conceptual changes without affecting views) and Physical (storage
changes without affecting logic).


⫸ Which is harder to achieve, logical or physical data independence?
Answer: Logical data independence.


⫸ What are examples of conceptual changes requiring logical data
independence? Answer: Adding an attribute or creating a new
relation.


⫸ What are DBA responsibilities? Answer: Database design,
enforcing constraints, backups, performance tuning, and user support.


⫸ What are the types of database languages? Answer: Data
Definition Language (DDL) and Data Manipulation Language
(DML).


⫸ What does DDL do? Answer: Defines database schemas and
constraints.


⫸ What does DML do? Answer: Queries, inserts, updates, and
deletes data.