WGU D440 Objective Assessment (OA) Practice Exam 2026 UPDATE
1. Which normal form requires the removal of partial functional dependencies, where an
attribute is dependent on only part of a composite primary key?
A. First Normal Form (1NF)
B. Third Normal Form (3NF)
C. Second Normal Form (2NF)
D. Boyce-Codd Normal Form (BCNF)
Answer: C
Rationale: Second Normal Form (2NF) specifically addresses partial functional
dependencies. A table is in 2NF if it is in 1NF and all non-key attributes are fully functional
dependent on the entire primary key.
2. In a SQL query, which clause is used to filter groups created by the GROUP BY clause?
A. WHERE
B. HAVING
C. ORDER BY
D. SELECT
Answer: B
,Rationale: The HAVING clause is used to filter groups based on a condition, whereas the
WHERE clause is used to filter individual rows before they are grouped.
3. What is the primary purpose of a Foreign Key in a relational database?
A. To uniquely identify each record in a table.
B. To improve the performance of search queries.
C. To establish and enforce a link between data in two tables.
D. To ensure that a column cannot contain NULL values.
Answer: C
Rationale: A Foreign Key is a field in one table that refers to the Primary Key in another
table, establishing a relationship and maintaining referential integrity between the two.
4. Which SQL statement is used to remove all records from a table without deleting the table
structure itself?
A. DELETE
B. DROP
C. TRUNCATE
D. REMOVE
Answer: C
, Rationale: TRUNCATE is a DDL command that removes all rows from a table, but the table
structure and its columns, constraints, and indexes remain intact. DELETE is DML and can
be used with a WHERE clause.
5. Which of the following describes a ‘transitive dependency’ in the context of database
normalization?
A. Multiple attributes depend on the same primary key.
B. A non-key attribute depends on a part of the primary key.
C. A primary key depends on a foreign key.
D. A non-key attribute depends on another non-key attribute.
Answer: D
Rationale: Transitive dependency occurs when a non-key attribute is dependent on
another non-key attribute. Removing these dependencies is the requirement for moving
from 2NF to 3NF.
6. In an Entity-Relationship Diagram (ERD), what does a ‘diamond’ symbol typically
represent?
A. A Relationship
B. An Attribute
C. An Entity
D. A Weak Entity
1. Which normal form requires the removal of partial functional dependencies, where an
attribute is dependent on only part of a composite primary key?
A. First Normal Form (1NF)
B. Third Normal Form (3NF)
C. Second Normal Form (2NF)
D. Boyce-Codd Normal Form (BCNF)
Answer: C
Rationale: Second Normal Form (2NF) specifically addresses partial functional
dependencies. A table is in 2NF if it is in 1NF and all non-key attributes are fully functional
dependent on the entire primary key.
2. In a SQL query, which clause is used to filter groups created by the GROUP BY clause?
A. WHERE
B. HAVING
C. ORDER BY
D. SELECT
Answer: B
,Rationale: The HAVING clause is used to filter groups based on a condition, whereas the
WHERE clause is used to filter individual rows before they are grouped.
3. What is the primary purpose of a Foreign Key in a relational database?
A. To uniquely identify each record in a table.
B. To improve the performance of search queries.
C. To establish and enforce a link between data in two tables.
D. To ensure that a column cannot contain NULL values.
Answer: C
Rationale: A Foreign Key is a field in one table that refers to the Primary Key in another
table, establishing a relationship and maintaining referential integrity between the two.
4. Which SQL statement is used to remove all records from a table without deleting the table
structure itself?
A. DELETE
B. DROP
C. TRUNCATE
D. REMOVE
Answer: C
, Rationale: TRUNCATE is a DDL command that removes all rows from a table, but the table
structure and its columns, constraints, and indexes remain intact. DELETE is DML and can
be used with a WHERE clause.
5. Which of the following describes a ‘transitive dependency’ in the context of database
normalization?
A. Multiple attributes depend on the same primary key.
B. A non-key attribute depends on a part of the primary key.
C. A primary key depends on a foreign key.
D. A non-key attribute depends on another non-key attribute.
Answer: D
Rationale: Transitive dependency occurs when a non-key attribute is dependent on
another non-key attribute. Removing these dependencies is the requirement for moving
from 2NF to 3NF.
6. In an Entity-Relationship Diagram (ERD), what does a ‘diamond’ symbol typically
represent?
A. A Relationship
B. An Attribute
C. An Entity
D. A Weak Entity
