WGU D426 Data Management – Foundations (LWO2) Objective Assessment | OA V1
and V2 | Questions and Answers – 2026 Update | 100% Correct.
Question 1
Which of the following best defines a relational database management system (RDBMS)?
A. A software system that stores data in flat files without relationships between data elements
B. A software system that organizes data into tables consisting of rows and columns and enforces
relationships between those tables using keys
C. A spreadsheet application used primarily for financial calculations
D. A programming language used to create web applications
Correct Answer: B
Explanation:
An RDBMS organizes data into structured tables with rows (records) and columns (attributes). It
enforces relationships using primary keys and foreign keys, supports SQL querying, and
maintains integrity constraints.
Question 2
In a relational table, what is the primary purpose of a primary key?
A. To allow duplicate values within a column
B. To uniquely identify each row within the table
C. To create a backup copy of the table
D. To encrypt sensitive data
Correct Answer: B
Explanation:
A primary key uniquely identifies each record in a table. It must contain unique values and
cannot be NULL.
Question 3
Which normal form eliminates repeating groups and ensures that each column contains atomic
(indivisible) values?
A. Second Normal Form (2NF)
B. Third Normal Form (3NF)
,C. First Normal Form (1NF)
D. Boyce-Codd Normal Form (BCNF)
Correct Answer: C
Explanation:
First Normal Form requires that each field contains atomic values and eliminates repeating
groups.
Question 4
What is the result of the following SQL statement?
SELECT * FROM Customers WHERE City = 'Chicago';
A. It deletes all customers located in Chicago
B. It updates customer records in Chicago
C. It retrieves all records from the Customers table where the City column equals 'Chicago'
D. It counts customers in Chicago
Correct Answer: C
Explanation:
The SELECT statement retrieves data. The WHERE clause filters rows based on a specified
condition.
Question 5
Which SQL command is used to remove a table from a database permanently?
A. DELETE
B. REMOVE
C. DROP
D. TRUNCATE
Correct Answer: C
Explanation:
DROP removes the entire table structure and its data permanently. DELETE removes rows;
TRUNCATE removes all rows but retains structure.
,Question 6
What is a foreign key?
A. A key used to encrypt data
B. A field that uniquely identifies records in its own table
C. A field in one table that references the primary key in another table
D. A duplicate of the primary key within the same table
Correct Answer: C
Explanation:
A foreign key creates a relationship between two tables by referencing a primary key in another
table.
Question 7
Which type of JOIN returns only rows that have matching values in both tables?
A. LEFT JOIN
B. RIGHT JOIN
C. INNER JOIN
D. FULL OUTER JOIN
Correct Answer: C
Explanation:
INNER JOIN returns only matching records from both tables.
Question 8
What does the SQL COUNT() function do?
A. Deletes duplicate rows
B. Calculates total numeric values
C. Returns the number of rows matching a condition
D. Sorts records alphabetically
Correct Answer: C
Explanation:
COUNT() returns the number of records that match a specified condition.
, Question 9
Which of the following statements about indexes is correct?
A. Indexes decrease query performance
B. Indexes improve search speed but may slow insert/update operations
C. Indexes store duplicate tables
D. Indexes replace primary keys
Correct Answer: B
Explanation:
Indexes speed up data retrieval but may reduce performance for inserts and updates.
Question 10
Which database model uses tables consisting of rows and columns?
A. Hierarchical model
B. Network model
C. Relational model
D. Object-oriented model
Correct Answer: C
Explanation:
The relational model organizes data into tables.
Question 11
Which SQL clause is used to sort query results?
A. SORT BY
B. GROUP BY
C. ORDER BY
D. ARRANGE
Correct Answer: C
and V2 | Questions and Answers – 2026 Update | 100% Correct.
Question 1
Which of the following best defines a relational database management system (RDBMS)?
A. A software system that stores data in flat files without relationships between data elements
B. A software system that organizes data into tables consisting of rows and columns and enforces
relationships between those tables using keys
C. A spreadsheet application used primarily for financial calculations
D. A programming language used to create web applications
Correct Answer: B
Explanation:
An RDBMS organizes data into structured tables with rows (records) and columns (attributes). It
enforces relationships using primary keys and foreign keys, supports SQL querying, and
maintains integrity constraints.
Question 2
In a relational table, what is the primary purpose of a primary key?
A. To allow duplicate values within a column
B. To uniquely identify each row within the table
C. To create a backup copy of the table
D. To encrypt sensitive data
Correct Answer: B
Explanation:
A primary key uniquely identifies each record in a table. It must contain unique values and
cannot be NULL.
Question 3
Which normal form eliminates repeating groups and ensures that each column contains atomic
(indivisible) values?
A. Second Normal Form (2NF)
B. Third Normal Form (3NF)
,C. First Normal Form (1NF)
D. Boyce-Codd Normal Form (BCNF)
Correct Answer: C
Explanation:
First Normal Form requires that each field contains atomic values and eliminates repeating
groups.
Question 4
What is the result of the following SQL statement?
SELECT * FROM Customers WHERE City = 'Chicago';
A. It deletes all customers located in Chicago
B. It updates customer records in Chicago
C. It retrieves all records from the Customers table where the City column equals 'Chicago'
D. It counts customers in Chicago
Correct Answer: C
Explanation:
The SELECT statement retrieves data. The WHERE clause filters rows based on a specified
condition.
Question 5
Which SQL command is used to remove a table from a database permanently?
A. DELETE
B. REMOVE
C. DROP
D. TRUNCATE
Correct Answer: C
Explanation:
DROP removes the entire table structure and its data permanently. DELETE removes rows;
TRUNCATE removes all rows but retains structure.
,Question 6
What is a foreign key?
A. A key used to encrypt data
B. A field that uniquely identifies records in its own table
C. A field in one table that references the primary key in another table
D. A duplicate of the primary key within the same table
Correct Answer: C
Explanation:
A foreign key creates a relationship between two tables by referencing a primary key in another
table.
Question 7
Which type of JOIN returns only rows that have matching values in both tables?
A. LEFT JOIN
B. RIGHT JOIN
C. INNER JOIN
D. FULL OUTER JOIN
Correct Answer: C
Explanation:
INNER JOIN returns only matching records from both tables.
Question 8
What does the SQL COUNT() function do?
A. Deletes duplicate rows
B. Calculates total numeric values
C. Returns the number of rows matching a condition
D. Sorts records alphabetically
Correct Answer: C
Explanation:
COUNT() returns the number of records that match a specified condition.
, Question 9
Which of the following statements about indexes is correct?
A. Indexes decrease query performance
B. Indexes improve search speed but may slow insert/update operations
C. Indexes store duplicate tables
D. Indexes replace primary keys
Correct Answer: B
Explanation:
Indexes speed up data retrieval but may reduce performance for inserts and updates.
Question 10
Which database model uses tables consisting of rows and columns?
A. Hierarchical model
B. Network model
C. Relational model
D. Object-oriented model
Correct Answer: C
Explanation:
The relational model organizes data into tables.
Question 11
Which SQL clause is used to sort query results?
A. SORT BY
B. GROUP BY
C. ORDER BY
D. ARRANGE
Correct Answer: C
