WGU D427 DATA MANAGEMENT
APPLICATIONS ADVANCED REVIEW
QUESTIONS AND ANSWERS
1. Which clause is used to filter the results of an aggregate function in a SELECT statement?
A. WHERE
B. ORDER BY
C. HAVING
D. GROUP BY
Answer: C
Conceptual Explanation: The HAVING clause is used specifically to filter records after an
aggregate function (like SUM or COUNT) has been applied, whereas WHERE filters rows
before aggregation.
2. In database normalization, a table is in Third Normal Form (3NF) if it is in 2NF and what
other condition is met?
A. It has no partial functional dependencies.
B. It contains a composite primary key.
,C. Every attribute is atomic.
D. It has no transitive functional dependencies.
Answer: D
Conceptual Explanation: 3NF requires that all non-key attributes are functionally
dependent only on the primary key, meaning there are no transitive dependencies.
3. Which SQL command is used to add a new column to an existing table?
A. UPDATE TABLE table_name ADD column_name datatype;
B. MODIFY TABLE table_name INSERT column_name datatype;
C. CHANGE TABLE table_name ADD column_name datatype;
D. ALTER TABLE table_name ADD column_name datatype;
Answer: D
Conceptual Explanation: The ALTER TABLE command is the standard DDL command
used to modify the structure of an existing table, including adding columns.
4. A LEFT JOIN returns all rows from the left table and the matched rows from the right table.
What happens when there is no match?
A. The result contains NULL values for every column of the right table.
B. An error is thrown by the SQL engine.
C. The row from the left table is excluded.
, D. The row from the right table is duplicated.
Answer: A
Conceptual Explanation: In a LEFT JOIN, if no match is found in the right table, the
columns associated with the right table will contain NULL values in the result set.
5. Which of the following is an example of a Data Manipulation Language (DML) command?
A. CREATE
B. TRUNCATE
C. DROP
D. DELETE
Answer: D
Conceptual Explanation: DELETE is a DML command because it deals with the data
within the tables. CREATE, DROP, and TRUNCATE are considered DDL (Data Definition
Language) commands.
6. Which integrity constraint ensures that a value in one table must match a value in another
table’s primary key?
A. Unique Constraint
B. Check Constraint
C. Primary Key Constraint
D. Foreign Key Constraint
APPLICATIONS ADVANCED REVIEW
QUESTIONS AND ANSWERS
1. Which clause is used to filter the results of an aggregate function in a SELECT statement?
A. WHERE
B. ORDER BY
C. HAVING
D. GROUP BY
Answer: C
Conceptual Explanation: The HAVING clause is used specifically to filter records after an
aggregate function (like SUM or COUNT) has been applied, whereas WHERE filters rows
before aggregation.
2. In database normalization, a table is in Third Normal Form (3NF) if it is in 2NF and what
other condition is met?
A. It has no partial functional dependencies.
B. It contains a composite primary key.
,C. Every attribute is atomic.
D. It has no transitive functional dependencies.
Answer: D
Conceptual Explanation: 3NF requires that all non-key attributes are functionally
dependent only on the primary key, meaning there are no transitive dependencies.
3. Which SQL command is used to add a new column to an existing table?
A. UPDATE TABLE table_name ADD column_name datatype;
B. MODIFY TABLE table_name INSERT column_name datatype;
C. CHANGE TABLE table_name ADD column_name datatype;
D. ALTER TABLE table_name ADD column_name datatype;
Answer: D
Conceptual Explanation: The ALTER TABLE command is the standard DDL command
used to modify the structure of an existing table, including adding columns.
4. A LEFT JOIN returns all rows from the left table and the matched rows from the right table.
What happens when there is no match?
A. The result contains NULL values for every column of the right table.
B. An error is thrown by the SQL engine.
C. The row from the left table is excluded.
, D. The row from the right table is duplicated.
Answer: A
Conceptual Explanation: In a LEFT JOIN, if no match is found in the right table, the
columns associated with the right table will contain NULL values in the result set.
5. Which of the following is an example of a Data Manipulation Language (DML) command?
A. CREATE
B. TRUNCATE
C. DROP
D. DELETE
Answer: D
Conceptual Explanation: DELETE is a DML command because it deals with the data
within the tables. CREATE, DROP, and TRUNCATE are considered DDL (Data Definition
Language) commands.
6. Which integrity constraint ensures that a value in one table must match a value in another
table’s primary key?
A. Unique Constraint
B. Check Constraint
C. Primary Key Constraint
D. Foreign Key Constraint
