WGU D426 DATA MANAGEMENT
FOUNDATIONS - EXAM PRACTICE
QUESTIONS AND CORRECT DETAILED
ANSWERS A+ GRADE
1. Which SQL clause is used to filter groups of rows after an aggregate function has been
applied?
A. WHERE
B. GROUP BY
C. HAVING
D. ORDER BY
Answer: C
Conceptual Explanation: The HAVING clause is specifically designed to filter groups
created by the GROUP BY clause, whereas WHERE filters individual rows before grouping
occurs.
2. A table is considered to be in Second Normal Form (2NF) if it is in 1NF and what other
condition is met?
A. All non-key attributes are functionally dependent on the entire primary key.
B. There are no transitive dependencies between non-key attributes.
,C. All multivalued attributes have been removed into separate tables.
D. Every determinant is a candidate key.
Answer: A
Conceptual Explanation: 2NF requires that there are no partial functional dependencies;
all non-prime attributes must depend on the whole primary key, not just a part of it.
3. In the relational model, which operation is used to combine all rows from two tables,
excluding duplicates, provided they have the same schema?
A. INTERSECT
B. UNION
C. JOIN
D. DIFFERENCE
Answer: B
Conceptual Explanation: The UNION operation combines results from two relations and
removes duplicates. Tables must be union-compatible (same number of columns and
compatible data types).
4. Which of the following is a Data Definition Language (DDL) command?
A. UPDATE
B. INSERT
C. ALTER
, D. SELECT
Answer: C
Conceptual Explanation: DDL commands like CREATE, ALTER, and DROP define or
modify the structure of the database. UPDATE and INSERT are DML (Data Manipulation
Language).
5. Which integrity constraint ensures that a foreign key value must match a primary key value
in a related table or be NULL?
A. Entity Integrity
B. Domain Integrity
C. Key Integrity
D. Referential Integrity
Answer: D
Conceptual Explanation: Referential integrity ensures consistency between related tables
by enforcing that foreign keys point to valid primary keys.
6. A ‘transitive dependency’ is the primary concern for which normal form?
A. 3NF
B. 2NF
C. 1NF
D. BCNF
FOUNDATIONS - EXAM PRACTICE
QUESTIONS AND CORRECT DETAILED
ANSWERS A+ GRADE
1. Which SQL clause is used to filter groups of rows after an aggregate function has been
applied?
A. WHERE
B. GROUP BY
C. HAVING
D. ORDER BY
Answer: C
Conceptual Explanation: The HAVING clause is specifically designed to filter groups
created by the GROUP BY clause, whereas WHERE filters individual rows before grouping
occurs.
2. A table is considered to be in Second Normal Form (2NF) if it is in 1NF and what other
condition is met?
A. All non-key attributes are functionally dependent on the entire primary key.
B. There are no transitive dependencies between non-key attributes.
,C. All multivalued attributes have been removed into separate tables.
D. Every determinant is a candidate key.
Answer: A
Conceptual Explanation: 2NF requires that there are no partial functional dependencies;
all non-prime attributes must depend on the whole primary key, not just a part of it.
3. In the relational model, which operation is used to combine all rows from two tables,
excluding duplicates, provided they have the same schema?
A. INTERSECT
B. UNION
C. JOIN
D. DIFFERENCE
Answer: B
Conceptual Explanation: The UNION operation combines results from two relations and
removes duplicates. Tables must be union-compatible (same number of columns and
compatible data types).
4. Which of the following is a Data Definition Language (DDL) command?
A. UPDATE
B. INSERT
C. ALTER
, D. SELECT
Answer: C
Conceptual Explanation: DDL commands like CREATE, ALTER, and DROP define or
modify the structure of the database. UPDATE and INSERT are DML (Data Manipulation
Language).
5. Which integrity constraint ensures that a foreign key value must match a primary key value
in a related table or be NULL?
A. Entity Integrity
B. Domain Integrity
C. Key Integrity
D. Referential Integrity
Answer: D
Conceptual Explanation: Referential integrity ensures consistency between related tables
by enforcing that foreign keys point to valid primary keys.
6. A ‘transitive dependency’ is the primary concern for which normal form?
A. 3NF
B. 2NF
C. 1NF
D. BCNF
