WGU D426 DATA MANAGEMENT
FOUNDATIONS FINAL EXAM PREP
QUESTIONS AND CORRECT DETAILED
ANSWERS A+ GRADE
1. Which normal form is reached when all partial functional dependencies have been
removed?
A. First Normal Form (1NF)
B. Third Normal Form (3NF)
C. Second Normal Form (2NF)
D. Boyce-Codd Normal Form (BCNF)
Answer: C
Conceptual Explanation: Second Normal Form (2NF) requires the table to be in 1NF and
all non-key attributes to be fully functionally dependent on the entire primary key, thus
removing partial dependencies.
2. In an Entity-Relationship Diagram (ERD), what does a dashed line usually represent
between two entities?
A. A non-identifying relationship
B. A strong relationship
,C. An identifying relationship
D. A mandatory relationship
Answer: A
Conceptual Explanation: In Crow’s foot notation, a dashed line represents a non-
identifying relationship where the child entity can exist independently of the parent.
3. Which SQL command is used to add a new column to an existing table?
A. UPDATE TABLE
B. ALTER TABLE
C. INSERT INTO
D. MODIFY TABLE
Answer: B
Conceptual Explanation: The ALTER TABLE command is used to add, delete, or modify
columns in an existing table structure (DDL).
4. What is the primary purpose of the ‘HAVING’ clause in SQL?
A. To filter rows before grouping occurs
B. To filter groups after the GROUP BY clause has been applied
C. To sort the final result set
D. To join multiple tables based on a condition
, Answer: B
Conceptual Explanation: The HAVING clause is used to filter the results of aggregate
functions, which cannot be handled by the WHERE clause.
5. Which type of join returns all rows from the left table and the matched rows from the right
table, filling with NULLs where there is no match?
A. INNER JOIN
B. FULL OUTER JOIN
C. LEFT JOIN
D. RIGHT JOIN
Answer: C
Conceptual Explanation: A LEFT JOIN returns all records from the left table and the
matched records from the right table; unmatched right-side columns are NULL.
6. In relational algebra, which operation is used to select a subset of columns from a relation?
A. Selection
B. Projection
C. Union
D. Join
Answer: B
FOUNDATIONS FINAL EXAM PREP
QUESTIONS AND CORRECT DETAILED
ANSWERS A+ GRADE
1. Which normal form is reached when all partial functional dependencies have been
removed?
A. First Normal Form (1NF)
B. Third Normal Form (3NF)
C. Second Normal Form (2NF)
D. Boyce-Codd Normal Form (BCNF)
Answer: C
Conceptual Explanation: Second Normal Form (2NF) requires the table to be in 1NF and
all non-key attributes to be fully functionally dependent on the entire primary key, thus
removing partial dependencies.
2. In an Entity-Relationship Diagram (ERD), what does a dashed line usually represent
between two entities?
A. A non-identifying relationship
B. A strong relationship
,C. An identifying relationship
D. A mandatory relationship
Answer: A
Conceptual Explanation: In Crow’s foot notation, a dashed line represents a non-
identifying relationship where the child entity can exist independently of the parent.
3. Which SQL command is used to add a new column to an existing table?
A. UPDATE TABLE
B. ALTER TABLE
C. INSERT INTO
D. MODIFY TABLE
Answer: B
Conceptual Explanation: The ALTER TABLE command is used to add, delete, or modify
columns in an existing table structure (DDL).
4. What is the primary purpose of the ‘HAVING’ clause in SQL?
A. To filter rows before grouping occurs
B. To filter groups after the GROUP BY clause has been applied
C. To sort the final result set
D. To join multiple tables based on a condition
, Answer: B
Conceptual Explanation: The HAVING clause is used to filter the results of aggregate
functions, which cannot be handled by the WHERE clause.
5. Which type of join returns all rows from the left table and the matched rows from the right
table, filling with NULLs where there is no match?
A. INNER JOIN
B. FULL OUTER JOIN
C. LEFT JOIN
D. RIGHT JOIN
Answer: C
Conceptual Explanation: A LEFT JOIN returns all records from the left table and the
matched records from the right table; unmatched right-side columns are NULL.
6. In relational algebra, which operation is used to select a subset of columns from a relation?
A. Selection
B. Projection
C. Union
D. Join
Answer: B
