WGU C170 – DATA MANAGEMENT APPLICATIONS – PRACTICE QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
CORE DOMAINS
Data Modeling and Entity Relationship Diagrams
Normalization and Database Design
SQL Data Definition Language (DDL)
SQL Data Manipulation Language (DML)
Advanced Joins and Subqueries
Database Security and User Access Control
Transaction Management and Concurrency
Business Intelligence and Data Warehousing
INTRODUCTION
The purpose of this comprehensive assessment is to evaluate a candidate's proficiency in the design,
implementation, and management of relational databases using industry-standard practices. This exam assesses
fundamental skills in translating business requirements into logical and physical data models, as well as the
technical mastery required to execute complex SQL queries for data retrieval and manipulation. The structure
utilizes a mix of conceptual multiple-choice and scenario-based questions to mirror real-world database
administration and development tasks. There is a strong emphasis on critical thinking, ethical data handling, and
decision-making regarding data integrity and security to ensure candidates are prepared for professional
environments.
SECTION ONE: QUESTIONS 1–100
1. Which SQL command is used to add a new column to an existing table?
,A. UPDATE TABLE
B. MODIFY TABLE
🟢 C. ALTER TABLE
D. INSERT INTO
🔴 RATIONALE: The ALTER TABLE statement is used to add, delete, or modify columns in an existing table
structure without recreating the table.
2. A database administrator needs to ensure that no two rows in a table have the same value in a specific
column, while also allowing for the possibility of a null value. Which constraint should be applied?
A. PRIMARY KEY
🟢 B. UNIQUE
C. NOT NULL
D. CHECK
🔴 RATIONALE: A UNIQUE constraint ensures all values in a column are different, but unlike a PRIMARY KEY, it
allows for the presence of NULL values.
3. In the context of the Three-Schema Architecture, which level describes how the data is actually stored on
the physical media?
🟢 A. Internal Level
B. Conceptual Level
C. External Level
D. Logical Level
🔴 RATIONALE: The Internal Level (or physical level) defines the physical storage structure and access paths of
the database.
, 4. Which normal form addresses the removal of partial functional dependencies where a non-key attribute is
dependent on only part of a composite primary key?
A. First Normal Form (1NF)
🟢 B. Second Normal Form (2NF)
C. Third Normal Form (3NF)
D. Boyce-Codd Normal Form (BCNF)
🔴 RATIONALE: To achieve 2NF, a table must be in 1NF and all non-key attributes must be fully functionally
dependent on the entire primary key.
5. You are tasked with retrieving a list of all customers whose last names start with the letter 'S'. Which
operator should be used in the WHERE clause?
A. MATCHES
B. CONTAINS
🟢 C. LIKE
D. START
🔴 RATIONALE: The LIKE operator is used in a WHERE clause to search for a specified pattern in a column,
typically using wildcards like '%'.
6. Which type of join returns all records from the left table and the matched records from the right table, filling
with NULLs where there is no match?
A. INNER JOIN
B. RIGHT JOIN
, 🟢 C. LEFT JOIN
D. FULL OUTER JOIN
🔴 RATIONALE: A LEFT JOIN (or LEFT OUTER JOIN) returns all rows from the left table and matching rows from
the right; unmatched rows from the right appear as NULL.
7. In an Entity Relationship Diagram (ERD), what does a "crow’s foot" symbol represent?
🟢 A. The "many" side of a relationship
B. The "one" side of a relationship
C. A mandatory relationship
D. An optional relationship
🔴 RATIONALE: In Crow's Foot notation, the three-pronged symbol signifies a "many" cardinality in a relationship
between entities.
8. Which of the following is considered a DML (Data Manipulation Language) command?
A. CREATE
🟢 B. UPDATE
C. DROP
D. GRANT
🔴 RATIONALE: DML commands like UPDATE, INSERT, and DELETE are used to manage data within existing
tables, whereas CREATE and DROP are DDL (Data Definition Language).
9. A database designer is creating a system for a library. A book can have multiple authors, and an author can
write multiple books. What type of relationship is this?
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
CORE DOMAINS
Data Modeling and Entity Relationship Diagrams
Normalization and Database Design
SQL Data Definition Language (DDL)
SQL Data Manipulation Language (DML)
Advanced Joins and Subqueries
Database Security and User Access Control
Transaction Management and Concurrency
Business Intelligence and Data Warehousing
INTRODUCTION
The purpose of this comprehensive assessment is to evaluate a candidate's proficiency in the design,
implementation, and management of relational databases using industry-standard practices. This exam assesses
fundamental skills in translating business requirements into logical and physical data models, as well as the
technical mastery required to execute complex SQL queries for data retrieval and manipulation. The structure
utilizes a mix of conceptual multiple-choice and scenario-based questions to mirror real-world database
administration and development tasks. There is a strong emphasis on critical thinking, ethical data handling, and
decision-making regarding data integrity and security to ensure candidates are prepared for professional
environments.
SECTION ONE: QUESTIONS 1–100
1. Which SQL command is used to add a new column to an existing table?
,A. UPDATE TABLE
B. MODIFY TABLE
🟢 C. ALTER TABLE
D. INSERT INTO
🔴 RATIONALE: The ALTER TABLE statement is used to add, delete, or modify columns in an existing table
structure without recreating the table.
2. A database administrator needs to ensure that no two rows in a table have the same value in a specific
column, while also allowing for the possibility of a null value. Which constraint should be applied?
A. PRIMARY KEY
🟢 B. UNIQUE
C. NOT NULL
D. CHECK
🔴 RATIONALE: A UNIQUE constraint ensures all values in a column are different, but unlike a PRIMARY KEY, it
allows for the presence of NULL values.
3. In the context of the Three-Schema Architecture, which level describes how the data is actually stored on
the physical media?
🟢 A. Internal Level
B. Conceptual Level
C. External Level
D. Logical Level
🔴 RATIONALE: The Internal Level (or physical level) defines the physical storage structure and access paths of
the database.
, 4. Which normal form addresses the removal of partial functional dependencies where a non-key attribute is
dependent on only part of a composite primary key?
A. First Normal Form (1NF)
🟢 B. Second Normal Form (2NF)
C. Third Normal Form (3NF)
D. Boyce-Codd Normal Form (BCNF)
🔴 RATIONALE: To achieve 2NF, a table must be in 1NF and all non-key attributes must be fully functionally
dependent on the entire primary key.
5. You are tasked with retrieving a list of all customers whose last names start with the letter 'S'. Which
operator should be used in the WHERE clause?
A. MATCHES
B. CONTAINS
🟢 C. LIKE
D. START
🔴 RATIONALE: The LIKE operator is used in a WHERE clause to search for a specified pattern in a column,
typically using wildcards like '%'.
6. Which type of join returns all records from the left table and the matched records from the right table, filling
with NULLs where there is no match?
A. INNER JOIN
B. RIGHT JOIN
, 🟢 C. LEFT JOIN
D. FULL OUTER JOIN
🔴 RATIONALE: A LEFT JOIN (or LEFT OUTER JOIN) returns all rows from the left table and matching rows from
the right; unmatched rows from the right appear as NULL.
7. In an Entity Relationship Diagram (ERD), what does a "crow’s foot" symbol represent?
🟢 A. The "many" side of a relationship
B. The "one" side of a relationship
C. A mandatory relationship
D. An optional relationship
🔴 RATIONALE: In Crow's Foot notation, the three-pronged symbol signifies a "many" cardinality in a relationship
between entities.
8. Which of the following is considered a DML (Data Manipulation Language) command?
A. CREATE
🟢 B. UPDATE
C. DROP
D. GRANT
🔴 RATIONALE: DML commands like UPDATE, INSERT, and DELETE are used to manage data within existing
tables, whereas CREATE and DROP are DDL (Data Definition Language).
9. A database designer is creating a system for a library. A book can have multiple authors, and an author can
write multiple books. What type of relationship is this?
