WGU D427 DATA MANAGEMENT
APPLICATIONS COMPREHENSIVE
EXAM QUESTIONS AND ANSWERS
1. Which SQL statement is used to remove all rows from a table without logging the
individual row deletions, effectively resetting the table?
A. DELETE FROM table_name;
B. DROP TABLE table_name;
C. REMOVE * FROM table_name;
D. TRUNCATE TABLE table_name;
Answer: D
Conceptual Explanation: TRUNCATE TABLE is a DDL operation that removes all rows
from a table. It is faster than DELETE because it does not log individual row deletions and
resets auto-increment counters.
2. A table is in Second Normal Form (2NF) if it is in 1NF and which of the following conditions
is met?
A. All non-key attributes are functional dependent on the entire primary key.
,B. There are no transitive dependencies.
C. It contains no multi-valued attributes.
D. Every determinant is a candidate key.
Answer: A
Conceptual Explanation: 2NF requires that all non-prime attributes are fully functionally
dependent on the whole primary key, meaning no partial dependencies exist.
3. In a relational database, what does ‘Referential Integrity’ ensure?
A. That every table has a primary key.
B. That data types are consistent across columns.
C. That a foreign key value must always match an existing primary key value in the related
table.
D. That no two rows in a table are identical.
Answer: C
Conceptual Explanation: Referential integrity ensures that relationships between tables
remain consistent, preventing orphaned records by requiring valid foreign key references.
4. Which of the following clauses is used to filter the results of an aggregate function in a
SELECT statement?
A. WHERE
B. ORDER BY
, C. GROUP BY
D. HAVING
Answer: D
Conceptual Explanation: The HAVING clause is used to filter record sets after groups have
been formed by a GROUP BY clause, whereas WHERE filters rows before grouping.
5. What is the primary difference between a INNER JOIN and a LEFT JOIN?
A. INNER JOIN is faster than LEFT JOIN regardless of the dataset.
B. INNER JOIN returns only matching rows; LEFT JOIN returns all rows from the left table
and matching rows from the right.
C. LEFT JOIN only returns rows that do not match in the right table.
D. There is no difference in the result set, only in performance.
Answer: B
Conceptual Explanation: INNER JOIN selects records that have matching values in both
tables. LEFT JOIN returns all records from the left table and the matched records from the
right table, filling with NULLs where there is no match.
6. Which normal form deals specifically with ‘transitive dependencies’?
A. First Normal Form (1NF)
B. Second Normal Form (2NF)
C. Third Normal Form (3NF)
APPLICATIONS COMPREHENSIVE
EXAM QUESTIONS AND ANSWERS
1. Which SQL statement is used to remove all rows from a table without logging the
individual row deletions, effectively resetting the table?
A. DELETE FROM table_name;
B. DROP TABLE table_name;
C. REMOVE * FROM table_name;
D. TRUNCATE TABLE table_name;
Answer: D
Conceptual Explanation: TRUNCATE TABLE is a DDL operation that removes all rows
from a table. It is faster than DELETE because it does not log individual row deletions and
resets auto-increment counters.
2. A table is in Second Normal Form (2NF) if it is in 1NF and which of the following conditions
is met?
A. All non-key attributes are functional dependent on the entire primary key.
,B. There are no transitive dependencies.
C. It contains no multi-valued attributes.
D. Every determinant is a candidate key.
Answer: A
Conceptual Explanation: 2NF requires that all non-prime attributes are fully functionally
dependent on the whole primary key, meaning no partial dependencies exist.
3. In a relational database, what does ‘Referential Integrity’ ensure?
A. That every table has a primary key.
B. That data types are consistent across columns.
C. That a foreign key value must always match an existing primary key value in the related
table.
D. That no two rows in a table are identical.
Answer: C
Conceptual Explanation: Referential integrity ensures that relationships between tables
remain consistent, preventing orphaned records by requiring valid foreign key references.
4. Which of the following clauses is used to filter the results of an aggregate function in a
SELECT statement?
A. WHERE
B. ORDER BY
, C. GROUP BY
D. HAVING
Answer: D
Conceptual Explanation: The HAVING clause is used to filter record sets after groups have
been formed by a GROUP BY clause, whereas WHERE filters rows before grouping.
5. What is the primary difference between a INNER JOIN and a LEFT JOIN?
A. INNER JOIN is faster than LEFT JOIN regardless of the dataset.
B. INNER JOIN returns only matching rows; LEFT JOIN returns all rows from the left table
and matching rows from the right.
C. LEFT JOIN only returns rows that do not match in the right table.
D. There is no difference in the result set, only in performance.
Answer: B
Conceptual Explanation: INNER JOIN selects records that have matching values in both
tables. LEFT JOIN returns all records from the left table and the matched records from the
right table, filling with NULLs where there is no match.
6. Which normal form deals specifically with ‘transitive dependencies’?
A. First Normal Form (1NF)
B. Second Normal Form (2NF)
C. Third Normal Form (3NF)
