WGU C175/D426 DATA MANAGEMENT FOUNDATIONS OA EXAM
ACTUAL EXAM 2026 LATEST VERSION 150 QUESTIONS AND CORRECT
VERIFIED ANSWERS WITH RATIONALES )/ALREADY GRADED A+
This set of 150 practice questions covers key topics in data management, including relational
databases, SQL queries, NoSQL databases, normalization/denormalization, database keys,
transactions, indexing, data types, and data warehousing. The questions are intermixed to
reflect the variety and structure of the WGU C175/D426 OA, helping students strengthen both
conceptual understanding and practical skills. Each question includes the correct answer
(marked in red) and a brief rationale, providing insight into why the answer is correct,
reinforcing learning, and improving exam readiness.
The questions range from basic SQL operations and data modeling to advanced concepts like
OLTP vs OLAP, transaction properties, and big data considerations, making it a
comprehensive review tool.
1. Which of the following best describes the difference between data and information?
A. Data is processed, and information is raw facts
B. Data is raw facts, and information is processed for meaning
C. Data and information are the same
D. Information cannot be stored in a database
Rationale: Data refers to raw facts, whereas information is meaningful data after processing.
2. Which SQL statement is used to remove a record from a table?
A. INSERT
B. UPDATE
C. DELETE
D. SELECT
Rationale: The DELETE statement removes existing rows from a table.
3. What is the main purpose of a primary key in a relational database?
A. To allow duplicate records
B. To uniquely identify each record
C. To enforce data privacy
D. To connect two unrelated databases
Rationale: A primary key ensures each row in a table is uniquely identifiable.
,4. Which of the following is an example of a NoSQL database?
A. MySQL
B. Oracle
C. MongoDB
D. Microsoft Access
Rationale: MongoDB is a document-oriented NoSQL database, unlike relational databases.
5. In SQL, which clause is used to filter rows based on a condition?
A. ORDER BY
B. WHERE
C. GROUP BY
D. HAVING
Rationale: The WHERE clause filters rows that meet a specified condition.
6. What does normalization in database design aim to achieve?
A. Reduce redundancy and improve data integrity
B. Increase data duplication
C. Make queries slower
D. Prevent users from accessing the database
Rationale: Normalization organizes data to minimize redundancy and dependency.
7. Which SQL keyword is used to sort the result set?
A. ORDER BY
B. GROUP BY
C. WHERE
D. JOIN
Rationale: ORDER BY arranges query results in ascending or descending order.
8. Which type of relationship is represented when one record in a table can relate to many records in
another table?
A. One-to-One
B. One-to-Many
C. Many-to-Many
D. None of the above
Rationale: One-to-many relationships are common in relational databases (e.g., a customer with many
orders).
,9. Which of the following is an example of data integrity enforcement?
A. Using NULL values everywhere
B. Implementing foreign keys
C. Ignoring validation rules
D. Storing data in multiple formats
Rationale: Foreign keys enforce referential integrity between tables.
10. In SQL, which command is used to retrieve data from a table?
A. SELECT
B. INSERT
C. UPDATE
D. DELETE
Rationale: SELECT is used to query and retrieve data from a database.
11. Which database model stores data in tables with rows and columns?
A. Relational
B. Hierarchical
C. Network
D. Object-oriented
Rationale: Relational databases use structured tables to store data.
12. Which statement about backup and recovery is true?
A. Backups are optional
B. Recovery ensures data can be restored after a loss
C. Recovery deletes old data
D. Backup and recovery are unrelated
Rationale: Backups and recovery plans prevent permanent data loss.
13. Which SQL clause is used with aggregate functions to filter groups?
A. WHERE
B. HAVING
C. ORDER BY
D. GROUP BY
Rationale: HAVING filters the results of aggregated data after grouping.
, 14. Which is a common attribute of a cloud-based database?
A. Limited scalability
B. High maintenance hardware requirement
C. On-demand access and scalability
D. Only supports local users
Rationale: Cloud databases offer scalability and accessibility without local infrastructure.
15. In an ER diagram, a diamond shape represents:
A. Entity
B. Attribute
C. Relationship
D. Table
Rationale: In ER diagrams, diamonds denote relationships between entities.
16. Which of the following is NOT a characteristic of big data?
A. Volume
B. Velocity
C. Variety
D. Validity
Rationale: Big Data is defined by volume, velocity, and variety; validity is related to data quality, not
definition.
17. A foreign key in a table:
A. Uniquely identifies the row in its table
B. Links to a primary key in another table
C. Cannot be NULL
D. Is used only in NoSQL databases
Rationale: Foreign keys establish referential integrity between tables.
18. Which SQL statement modifies existing records in a table?
A. INSERT
B. UPDATE
C. DELETE
D. SELECT
Rationale: UPDATE is used to change values of existing rows.
ACTUAL EXAM 2026 LATEST VERSION 150 QUESTIONS AND CORRECT
VERIFIED ANSWERS WITH RATIONALES )/ALREADY GRADED A+
This set of 150 practice questions covers key topics in data management, including relational
databases, SQL queries, NoSQL databases, normalization/denormalization, database keys,
transactions, indexing, data types, and data warehousing. The questions are intermixed to
reflect the variety and structure of the WGU C175/D426 OA, helping students strengthen both
conceptual understanding and practical skills. Each question includes the correct answer
(marked in red) and a brief rationale, providing insight into why the answer is correct,
reinforcing learning, and improving exam readiness.
The questions range from basic SQL operations and data modeling to advanced concepts like
OLTP vs OLAP, transaction properties, and big data considerations, making it a
comprehensive review tool.
1. Which of the following best describes the difference between data and information?
A. Data is processed, and information is raw facts
B. Data is raw facts, and information is processed for meaning
C. Data and information are the same
D. Information cannot be stored in a database
Rationale: Data refers to raw facts, whereas information is meaningful data after processing.
2. Which SQL statement is used to remove a record from a table?
A. INSERT
B. UPDATE
C. DELETE
D. SELECT
Rationale: The DELETE statement removes existing rows from a table.
3. What is the main purpose of a primary key in a relational database?
A. To allow duplicate records
B. To uniquely identify each record
C. To enforce data privacy
D. To connect two unrelated databases
Rationale: A primary key ensures each row in a table is uniquely identifiable.
,4. Which of the following is an example of a NoSQL database?
A. MySQL
B. Oracle
C. MongoDB
D. Microsoft Access
Rationale: MongoDB is a document-oriented NoSQL database, unlike relational databases.
5. In SQL, which clause is used to filter rows based on a condition?
A. ORDER BY
B. WHERE
C. GROUP BY
D. HAVING
Rationale: The WHERE clause filters rows that meet a specified condition.
6. What does normalization in database design aim to achieve?
A. Reduce redundancy and improve data integrity
B. Increase data duplication
C. Make queries slower
D. Prevent users from accessing the database
Rationale: Normalization organizes data to minimize redundancy and dependency.
7. Which SQL keyword is used to sort the result set?
A. ORDER BY
B. GROUP BY
C. WHERE
D. JOIN
Rationale: ORDER BY arranges query results in ascending or descending order.
8. Which type of relationship is represented when one record in a table can relate to many records in
another table?
A. One-to-One
B. One-to-Many
C. Many-to-Many
D. None of the above
Rationale: One-to-many relationships are common in relational databases (e.g., a customer with many
orders).
,9. Which of the following is an example of data integrity enforcement?
A. Using NULL values everywhere
B. Implementing foreign keys
C. Ignoring validation rules
D. Storing data in multiple formats
Rationale: Foreign keys enforce referential integrity between tables.
10. In SQL, which command is used to retrieve data from a table?
A. SELECT
B. INSERT
C. UPDATE
D. DELETE
Rationale: SELECT is used to query and retrieve data from a database.
11. Which database model stores data in tables with rows and columns?
A. Relational
B. Hierarchical
C. Network
D. Object-oriented
Rationale: Relational databases use structured tables to store data.
12. Which statement about backup and recovery is true?
A. Backups are optional
B. Recovery ensures data can be restored after a loss
C. Recovery deletes old data
D. Backup and recovery are unrelated
Rationale: Backups and recovery plans prevent permanent data loss.
13. Which SQL clause is used with aggregate functions to filter groups?
A. WHERE
B. HAVING
C. ORDER BY
D. GROUP BY
Rationale: HAVING filters the results of aggregated data after grouping.
, 14. Which is a common attribute of a cloud-based database?
A. Limited scalability
B. High maintenance hardware requirement
C. On-demand access and scalability
D. Only supports local users
Rationale: Cloud databases offer scalability and accessibility without local infrastructure.
15. In an ER diagram, a diamond shape represents:
A. Entity
B. Attribute
C. Relationship
D. Table
Rationale: In ER diagrams, diamonds denote relationships between entities.
16. Which of the following is NOT a characteristic of big data?
A. Volume
B. Velocity
C. Variety
D. Validity
Rationale: Big Data is defined by volume, velocity, and variety; validity is related to data quality, not
definition.
17. A foreign key in a table:
A. Uniquely identifies the row in its table
B. Links to a primary key in another table
C. Cannot be NULL
D. Is used only in NoSQL databases
Rationale: Foreign keys establish referential integrity between tables.
18. Which SQL statement modifies existing records in a table?
A. INSERT
B. UPDATE
C. DELETE
D. SELECT
Rationale: UPDATE is used to change values of existing rows.
