WGU D427 DATA MANAGEMENT
APPLICATIONS COMPREHENSIVE
PRACTICE EXAM QUESTIONS AND
ANSWERS
1. Which SQL statement is used to remove all records from a table without deleting the table
structure itself, and is generally faster than deleting rows one by one?
A. TRUNCATE TABLE table_name
B. DROP TABLE table_name
C. DELETE FROM table_name
D. REMOVE ALL FROM table_name
Answer: A
Conceptual Explanation: TRUNCATE TABLE removes all rows from a table, but the table
structure and its columns, constraints, indexes, and so on remain. It is faster than DELETE
because it does not log individual row deletions.
2. In a relational database, what does the term ‘Referential Integrity’ ensure?
A. That all primary keys are unique across the entire database.
,B. That every table has at least one index to speed up queries.
C. That data is encrypted before being stored in the database.
D. That a value in a foreign key column must match a value in the primary key of the
related table.
Answer: D
Conceptual Explanation: Referential integrity is a property of data stating that all its
references are valid. In the context of relational databases, it requires every value of one
attribute (column) of a relation (table) to exist as a value of another attribute in a different
(or the same) relation.
3. Which normal form requires that all non-key attributes are fully functionally dependent on
the entire primary key, thereby removing partial dependencies?
A. First Normal Form (1NF)
B. Boyce-Codd Normal Form (BCNF)
C. Third Normal Form (3NF)
D. Second Normal Form (2NF)
Answer: D
Conceptual Explanation: Second Normal Form (2NF) requires that the table is in 1NF and
that there are no partial functional dependencies on a composite primary key.
, 4. Which SQL keyword is used to sort the result-set in descending order?
A. DESC
B. ORDER DESC
C. SORT DESC
D. REVERSE
Answer: A
Conceptual Explanation: The DESC keyword is used within an ORDER BY clause to sort
the results in descending order.
5. When using the GROUP BY clause, which clause must be used instead of WHERE to filter
the results based on an aggregate function?
A. FILTER
B. HAVING
C. LIMIT
D. WHEN
Answer: B
Conceptual Explanation: The HAVING clause was added to SQL because the WHERE
keyword could not be used with aggregate functions.
6. What is the effect of a LEFT JOIN between Table A and Table B?
A. It returns only the rows that have matching values in both tables.
APPLICATIONS COMPREHENSIVE
PRACTICE EXAM QUESTIONS AND
ANSWERS
1. Which SQL statement is used to remove all records from a table without deleting the table
structure itself, and is generally faster than deleting rows one by one?
A. TRUNCATE TABLE table_name
B. DROP TABLE table_name
C. DELETE FROM table_name
D. REMOVE ALL FROM table_name
Answer: A
Conceptual Explanation: TRUNCATE TABLE removes all rows from a table, but the table
structure and its columns, constraints, indexes, and so on remain. It is faster than DELETE
because it does not log individual row deletions.
2. In a relational database, what does the term ‘Referential Integrity’ ensure?
A. That all primary keys are unique across the entire database.
,B. That every table has at least one index to speed up queries.
C. That data is encrypted before being stored in the database.
D. That a value in a foreign key column must match a value in the primary key of the
related table.
Answer: D
Conceptual Explanation: Referential integrity is a property of data stating that all its
references are valid. In the context of relational databases, it requires every value of one
attribute (column) of a relation (table) to exist as a value of another attribute in a different
(or the same) relation.
3. Which normal form requires that all non-key attributes are fully functionally dependent on
the entire primary key, thereby removing partial dependencies?
A. First Normal Form (1NF)
B. Boyce-Codd Normal Form (BCNF)
C. Third Normal Form (3NF)
D. Second Normal Form (2NF)
Answer: D
Conceptual Explanation: Second Normal Form (2NF) requires that the table is in 1NF and
that there are no partial functional dependencies on a composite primary key.
, 4. Which SQL keyword is used to sort the result-set in descending order?
A. DESC
B. ORDER DESC
C. SORT DESC
D. REVERSE
Answer: A
Conceptual Explanation: The DESC keyword is used within an ORDER BY clause to sort
the results in descending order.
5. When using the GROUP BY clause, which clause must be used instead of WHERE to filter
the results based on an aggregate function?
A. FILTER
B. HAVING
C. LIMIT
D. WHEN
Answer: B
Conceptual Explanation: The HAVING clause was added to SQL because the WHERE
keyword could not be used with aggregate functions.
6. What is the effect of a LEFT JOIN between Table A and Table B?
A. It returns only the rows that have matching values in both tables.
