B CompE Bachelor of Computer Engineering Database Management Systems

Question 1

Which normal form eliminates partial dependencies on a composite primary key?

Accepted Answer

Second Normal Form (2NF)

Answer

2NF removes partial dependencies by ensuring every non-key attribute is fully functionally dependent on the entire primary key.

Question 2

What SQL clause is used to filter results after aggregation?

Accepted Answer

HAVING

Answer

The HAVING clause filters grouped results from aggregate functions, whereas WHERE filters individual rows before grouping.

Question 3

Which type of JOIN returns all rows from both tables, with NULLs where there is no match?

Accepted Answer

FULL OUTER JOIN

Answer

A FULL OUTER JOIN returns all rows from both tables, filling unmatched columns with NULL values.

Question 4

What is a foreign key in a relational database?

Accepted Answer

A primary key of another table referenced by the current table

Answer

A foreign key is a column (or set of columns) in one table that references the primary key of another table to enforce referential integrity.

Question 5

Which SQL command removes all rows from a table without deleting the table structure?

Accepted Answer

TRUNCATE

Answer

TRUNCATE removes all rows from a table quickly without logging individual row deletions, while keeping the table structure intact.

B CompE Bachelor of Computer Engineering Practice Test