CPP Database Programming & SQL 3

Question 1

Which approach is the most effective way to prevent SQL injection attacks in application code?

Accepted Answer

Using parameterized queries (prepared statements)

Answer

Parameterized queries separate SQL code from data, so user input is always treated as a literal value and can never be interpreted as SQL syntax.

Question 2

In the CAP theorem for distributed databases, which two properties can be simultaneously guaranteed during a network partition?

Accepted Answer

Consistency and Partition Tolerance, or Availability and Partition Tolerance — but not all three

Answer

The CAP theorem states that during a network partition, a distributed system can guarantee either Consistency or Availability but not both; Partition Tolerance is mandatory in distributed systems.

Question 3

What is the key difference between DELETE and TRUNCATE in SQL?

Accepted Answer

DELETE can be rolled back and supports WHERE; TRUNCATE is typically faster and non-recoverable without a transaction

Answer

DELETE removes rows one by one with full transaction log entries and supports a WHERE clause; TRUNCATE removes all rows rapidly (often by deallocating pages) and in most databases cannot be filtered by WHERE.

Question 4

Which normal form eliminates multi-valued dependencies, where one attribute independently determines two or more other attributes?

Accepted Answer

Fourth Normal Form (4NF)

Answer

4NF extends BCNF by requiring that a table have no non-trivial multi-valued dependencies — cases where one key independently determines two separate sets of values.

Question 5

What does the SQL keyword DISTINCT do when used in a SELECT statement?

Accepted Answer

Removes duplicate rows from the query result

Answer

DISTINCT instructs the database to return only unique rows, eliminating any duplicate combinations of the selected columns from the result set.

CPP - Certified Professional Programmer Practice Test

CPP - Certified Professional Programmer Practice Test

CPP Database Programming & SQL 3