WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
WGU C170 Data Management Applications
Comprehensive Exam Study Guide
Over 400 Questions & Answers with Verified Rationales
420 Questions · 13 Competency Sections · Aligned to WGU C170 Objective Assessment Blueprint · 2026/2027 Latest Update
Exam Overview: This study guide is organized into thirteen competency-aligned sections covering the WGU
C170 Data Management Applications objective assessment blueprint: (1) Database Fundamentals and the
Relational Model; (2) Entity-Relationship Modeling and Database Design; (3) Normalization and Functional
Dependencies; (4) Data Definition Language (DDL) and Constraints; (5) Data Manipulation Language (DML)
and Transactions; (6) Basic Querying; (7) Joins and Set Operations; (8) Subqueries and Advanced Querying; (9)
Aggregate Functions, GROUP BY, and HAVING; (10) Views, Stored Procedures, Functions, and Triggers; (11)
Indexes, Performance Tuning, and Query Optimization; (12) Database Administration, Security, and Transaction
Management; and (13) Data Warehousing, Business Intelligence, NoSQL, and Cloud Databases. Each question is
multiple choice with four options (A-D) and exactly one correct answer. Rationales double as study guide
content, identifying the correct option and contrasting common SQL and database design misconceptions
represented in distractors.
Section Map: Q1-40 Database Fundamentals & Relational Model · Q41-80 ER Modeling & Database Design ·
Q81-115 Normalization & Functional Dependencies · Q116-150 DDL & Constraints · Q151-180 DML &
Transactions · Q181-215 Basic Querying · Q216-250 Joins & Set Operations · Q251-285 Subqueries &
Advanced Querying · Q286-315 Aggregate Functions, GROUP BY, HAVING · Q316-345 Views, Stored
Procedures, Functions, Triggers · Q346-370 Indexes, Performance Tuning · Q371-395 Database Administration,
Security, Transactions · Q396-420 Data Warehousing, BI, NoSQL, Cloud Databases.
Verified Answer Note: Each rationale embeds confirmation against current SQL standards (ANSI/ISO
SQL:1999, 2003, 2008, 2011, 2016, 2019, 2023), relational theory (Codd, Armstrong axioms), normalization
principles (1NF-5NF, BCNF, DKNF), and major RDBMS dialects (MySQL, PostgreSQL, Oracle, SQL Server).
Commonly confused pairs are explicitly addressed: WHERE vs. HAVING, INNER vs. LEFT vs. RIGHT vs.
FULL OUTER JOIN, IN vs. EXISTS vs. JOIN, UNION vs. UNION ALL, DELETE vs. TRUNCATE vs.
DROP, BCNF vs. 3NF, READ UNCOMMITTED vs. COMMITTED vs. REPEATABLE READ vs.
SERIALIZABLE, and OLTP vs. OLAP.
Section 1: Database Fundamentals and the Relational Model
Q1. [Recall] Which statement best describes a Database Management System (DBMS)?
A. Software that enables users to define, create, maintain, and control access to a database, providing data
independence, concurrency control, and recovery services. [CORRECT]
B. A collection of related data stored in a single file.
C. An operating system service for file storage.
D. A programming language used to query data.
Correct Answer: A
Page 1
,WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
Rationale: A DBMS is software that manages databases—defining (DDL), manipulating (DML), and controlling
access (DCL) to data while providing concurrency, recovery, and data independence. C170 Module 1 frames
DBMS as the bridge between physical storage and logical schema.
Q2. [Recall] Which advantage of a database system over a file-based system is most directly tied to reducing
data duplication?
A. Data independence.
B. Increased program-data dependence.
C. Minimal data redundancy (controlled redundancy) — databases normalize data into related tables,
reducing duplication and the anomalies that come with it. [CORRECT]
D. Higher hardware cost.
Correct Answer: C
Rationale: A core advantage of database systems is minimal controlled redundancy; normalization reduces
duplication and the resulting insert/update/delete anomalies. Data independence (A) is a separate advantage
concerning schema insulation. C170 Module 1 contrasts file vs. database systems.
Q3. [Recall] Which term refers to a single row in a relational table, representing one entity instance?
A. Domain.
B. Attribute.
C. Tuple (or record) — a single row in a relation, representing one entity instance with a value for each
attribute. [CORRECT]
D. Schema.
Correct Answer: C
Rationale: A tuple is a single row (record) in a relation; an attribute (A) is a column, a domain (C) is the set of
allowable values for an attribute, and a schema (D) is the structure definition. C170 Module 2 introduces relational
terminology.
Q4. [Recall] Which term refers to a column in a relational table?
A. Tuple.
B. Degree.
C. Attribute (or field) — a named column in a relation representing a property of the entity; each attribute
has an associated domain. [CORRECT]
D. Cardinality.
Correct Answer: C
Rationale: An attribute is a named column representing a property of the entity; the number of attributes is the
degree (arity) of the relation. Cardinality (C) is the number of tuples. C170 Module 2 covers relational terminology.
Q5. [Recall] Which term refers to the set of allowable values for one or more attributes?
A. Tuple.
B. Key.
C. Domain — the set of allowable values for an attribute (e.g., domain of gender may be {M, F, X});
enforces type and value constraints at the conceptual level. [CORRECT]
D. Schema.
Correct Answer: C
Rationale: A domain is the set of allowable values for one or more attributes; it enforces type and value constraints
conceptually before SQL CHECK constraints are applied. C170 Module 2 includes domain as a relational model
component.
Page 2
,WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
Q6. [Recall] Which statement best describes the degree of a relation?
A. The number of indexes.
B. The number of tuples (rows).
C. The number of foreign keys.
D. The number of attributes (columns) in the relation schema — also called arity. Cardinality refers to the
number of tuples. [CORRECT]
Correct Answer: D
Rationale: Degree (arity) = number of attributes in the relation schema; cardinality = number of tuples. C170
Module 2 distinguishes degree (columns) from cardinality (rows) — a commonly tested pair.
Q7. [Recall] Which statement best describes the cardinality of a relation?
A. The number of indexes.
B. The number of users.
C. The number of attributes.
D. The number of tuples (rows) currently in the relation; changes as data is inserted or deleted. Degree
refers to attributes. [CORRECT]
Correct Answer: D
Rationale: Cardinality = number of tuples currently in the relation; changes over time. Degree = number of
attributes (fixed by schema). C170 Module 2 includes this commonly-confused pair.
Q8. [Application] A relation has 5 attributes and currently contains 100 rows. What is its degree and cardinality?
A. Degree 5 (number of attributes), cardinality 100 (number of tuples). [CORRECT]
B. Degree 100, cardinality 5.
C. Degree 5, cardinality 5.
D. Degree 100, cardinality 100.
Correct Answer: A
Rationale: Degree = 5 (number of attributes/columns); cardinality = 100 (number of tuples/rows currently). C170
Module 2 tests this terminology distinction.
Q9. [Recall] Which integrity rule ensures that no primary key value may be NULL?
A. Referential integrity.
B. User-defined integrity.
C. Domain integrity.
D. Entity integrity — no primary key attribute (or part of a composite primary key) may be NULL,
ensuring each row is uniquely identifiable. [CORRECT]
Correct Answer: D
Rationale: Entity integrity requires that no primary key (or part of a composite PK) be NULL. Referential
integrity (A) governs foreign keys; domain (C) governs attribute values; user-defined (D) covers custom rules.
C170 Module 2 lists four integrity categories.
Q10. [Application] A table named Employee has a DepartmentID column that references
Department(DepartmentID). A user attempts to delete a Department row that has matching Employee rows.
Which integrity rule is at risk of being violated?
A. Referential integrity — the foreign key in Employee would reference a non-existent Department row if
the parent row is deleted. SQL handles this via ON DELETE CASCADE, SET NULL, RESTRICT, or NO
ACTION. [CORRECT]
B. Domain integrity.
C. Key integrity.
Page 3
, WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
D. Entity integrity.
Correct Answer: A
Rationale: Referential integrity requires that foreign key values match existing primary key values in the
referenced table or be NULL; deleting a parent row with existing child rows violates this unless the FK constraint
specifies CASCADE/SET NULL/SET DEFAULT. C170 Module 2 emphasizes referential integrity.
Q11. [Recall] Which type of key uniquely identifies each row in a table but is not chosen as the primary key?
A. Candidate key — a minimal set of attributes that uniquely identifies tuples; one is selected as the
primary key, the others become alternate keys. [CORRECT]
B. Surrogate key.
C. Foreign key.
D. Composite key.
Correct Answer: A
Rationale: A candidate key is a minimal unique identifier; one is chosen as PK, the others are alternate keys. A
composite key (C) is a multi-column key; a surrogate key (D) is an artificial identifier. C170 Module 2 covers key
types.
Q12. [Recall] Which key type is composed of two or more columns whose combination uniquely identifies a
row?
A. Composite key — multiple columns whose combined values uniquely identify each tuple (e.g., OrderID
+ ProductID in an order-line table). [CORRECT]
B. Surrogate key.
C. Foreign key.
D. Alternate key.
Correct Answer: A
Rationale: A composite key combines two or more columns to uniquely identify a tuple; common in junction
(associative) tables for many-to-many relationships. C170 Module 2 includes composite key definitions.
Q13. [Recall] Which key is an artificial, system-generated unique identifier with no business meaning?
A. Composite key.
B. Natural key.
C. Surrogate key — an artificial identifier (often an auto-increment integer or UUID) with no business
meaning; preferred when natural keys are unstable, complex, or sensitive. [CORRECT]
D. Foreign key.
Correct Answer: C
Rationale: A surrogate key is an artificial identifier (auto-increment, UUID) with no business meaning; preferred
when natural keys (SSN, email) are unstable, complex, or sensitive. C170 Module 2 contrasts natural vs. surrogate
keys.
Q14. [Recall] Which ANSI/ISO SQL standard introduced window functions (OVER clause), MERGE
statements, and XML support, forming the foundation for most modern RDBMS features?
A. SQL:1999 (SQL3) — introduced window functions, MERGE, recursive queries (WITH), and XML
support; subsequent standards (SQL:2003, 2006, 2008, 2011, 2016, 2019, 2023) added JSON,
polymorphic tables, and property graphs. [CORRECT]
B. SQL-92 only.
C. SQL-86.
D. SQL-89.
Correct Answer: A
Page 4
WGU C170 Data Management Applications
Comprehensive Exam Study Guide
Over 400 Questions & Answers with Verified Rationales
420 Questions · 13 Competency Sections · Aligned to WGU C170 Objective Assessment Blueprint · 2026/2027 Latest Update
Exam Overview: This study guide is organized into thirteen competency-aligned sections covering the WGU
C170 Data Management Applications objective assessment blueprint: (1) Database Fundamentals and the
Relational Model; (2) Entity-Relationship Modeling and Database Design; (3) Normalization and Functional
Dependencies; (4) Data Definition Language (DDL) and Constraints; (5) Data Manipulation Language (DML)
and Transactions; (6) Basic Querying; (7) Joins and Set Operations; (8) Subqueries and Advanced Querying; (9)
Aggregate Functions, GROUP BY, and HAVING; (10) Views, Stored Procedures, Functions, and Triggers; (11)
Indexes, Performance Tuning, and Query Optimization; (12) Database Administration, Security, and Transaction
Management; and (13) Data Warehousing, Business Intelligence, NoSQL, and Cloud Databases. Each question is
multiple choice with four options (A-D) and exactly one correct answer. Rationales double as study guide
content, identifying the correct option and contrasting common SQL and database design misconceptions
represented in distractors.
Section Map: Q1-40 Database Fundamentals & Relational Model · Q41-80 ER Modeling & Database Design ·
Q81-115 Normalization & Functional Dependencies · Q116-150 DDL & Constraints · Q151-180 DML &
Transactions · Q181-215 Basic Querying · Q216-250 Joins & Set Operations · Q251-285 Subqueries &
Advanced Querying · Q286-315 Aggregate Functions, GROUP BY, HAVING · Q316-345 Views, Stored
Procedures, Functions, Triggers · Q346-370 Indexes, Performance Tuning · Q371-395 Database Administration,
Security, Transactions · Q396-420 Data Warehousing, BI, NoSQL, Cloud Databases.
Verified Answer Note: Each rationale embeds confirmation against current SQL standards (ANSI/ISO
SQL:1999, 2003, 2008, 2011, 2016, 2019, 2023), relational theory (Codd, Armstrong axioms), normalization
principles (1NF-5NF, BCNF, DKNF), and major RDBMS dialects (MySQL, PostgreSQL, Oracle, SQL Server).
Commonly confused pairs are explicitly addressed: WHERE vs. HAVING, INNER vs. LEFT vs. RIGHT vs.
FULL OUTER JOIN, IN vs. EXISTS vs. JOIN, UNION vs. UNION ALL, DELETE vs. TRUNCATE vs.
DROP, BCNF vs. 3NF, READ UNCOMMITTED vs. COMMITTED vs. REPEATABLE READ vs.
SERIALIZABLE, and OLTP vs. OLAP.
Section 1: Database Fundamentals and the Relational Model
Q1. [Recall] Which statement best describes a Database Management System (DBMS)?
A. Software that enables users to define, create, maintain, and control access to a database, providing data
independence, concurrency control, and recovery services. [CORRECT]
B. A collection of related data stored in a single file.
C. An operating system service for file storage.
D. A programming language used to query data.
Correct Answer: A
Page 1
,WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
Rationale: A DBMS is software that manages databases—defining (DDL), manipulating (DML), and controlling
access (DCL) to data while providing concurrency, recovery, and data independence. C170 Module 1 frames
DBMS as the bridge between physical storage and logical schema.
Q2. [Recall] Which advantage of a database system over a file-based system is most directly tied to reducing
data duplication?
A. Data independence.
B. Increased program-data dependence.
C. Minimal data redundancy (controlled redundancy) — databases normalize data into related tables,
reducing duplication and the anomalies that come with it. [CORRECT]
D. Higher hardware cost.
Correct Answer: C
Rationale: A core advantage of database systems is minimal controlled redundancy; normalization reduces
duplication and the resulting insert/update/delete anomalies. Data independence (A) is a separate advantage
concerning schema insulation. C170 Module 1 contrasts file vs. database systems.
Q3. [Recall] Which term refers to a single row in a relational table, representing one entity instance?
A. Domain.
B. Attribute.
C. Tuple (or record) — a single row in a relation, representing one entity instance with a value for each
attribute. [CORRECT]
D. Schema.
Correct Answer: C
Rationale: A tuple is a single row (record) in a relation; an attribute (A) is a column, a domain (C) is the set of
allowable values for an attribute, and a schema (D) is the structure definition. C170 Module 2 introduces relational
terminology.
Q4. [Recall] Which term refers to a column in a relational table?
A. Tuple.
B. Degree.
C. Attribute (or field) — a named column in a relation representing a property of the entity; each attribute
has an associated domain. [CORRECT]
D. Cardinality.
Correct Answer: C
Rationale: An attribute is a named column representing a property of the entity; the number of attributes is the
degree (arity) of the relation. Cardinality (C) is the number of tuples. C170 Module 2 covers relational terminology.
Q5. [Recall] Which term refers to the set of allowable values for one or more attributes?
A. Tuple.
B. Key.
C. Domain — the set of allowable values for an attribute (e.g., domain of gender may be {M, F, X});
enforces type and value constraints at the conceptual level. [CORRECT]
D. Schema.
Correct Answer: C
Rationale: A domain is the set of allowable values for one or more attributes; it enforces type and value constraints
conceptually before SQL CHECK constraints are applied. C170 Module 2 includes domain as a relational model
component.
Page 2
,WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
Q6. [Recall] Which statement best describes the degree of a relation?
A. The number of indexes.
B. The number of tuples (rows).
C. The number of foreign keys.
D. The number of attributes (columns) in the relation schema — also called arity. Cardinality refers to the
number of tuples. [CORRECT]
Correct Answer: D
Rationale: Degree (arity) = number of attributes in the relation schema; cardinality = number of tuples. C170
Module 2 distinguishes degree (columns) from cardinality (rows) — a commonly tested pair.
Q7. [Recall] Which statement best describes the cardinality of a relation?
A. The number of indexes.
B. The number of users.
C. The number of attributes.
D. The number of tuples (rows) currently in the relation; changes as data is inserted or deleted. Degree
refers to attributes. [CORRECT]
Correct Answer: D
Rationale: Cardinality = number of tuples currently in the relation; changes over time. Degree = number of
attributes (fixed by schema). C170 Module 2 includes this commonly-confused pair.
Q8. [Application] A relation has 5 attributes and currently contains 100 rows. What is its degree and cardinality?
A. Degree 5 (number of attributes), cardinality 100 (number of tuples). [CORRECT]
B. Degree 100, cardinality 5.
C. Degree 5, cardinality 5.
D. Degree 100, cardinality 100.
Correct Answer: A
Rationale: Degree = 5 (number of attributes/columns); cardinality = 100 (number of tuples/rows currently). C170
Module 2 tests this terminology distinction.
Q9. [Recall] Which integrity rule ensures that no primary key value may be NULL?
A. Referential integrity.
B. User-defined integrity.
C. Domain integrity.
D. Entity integrity — no primary key attribute (or part of a composite primary key) may be NULL,
ensuring each row is uniquely identifiable. [CORRECT]
Correct Answer: D
Rationale: Entity integrity requires that no primary key (or part of a composite PK) be NULL. Referential
integrity (A) governs foreign keys; domain (C) governs attribute values; user-defined (D) covers custom rules.
C170 Module 2 lists four integrity categories.
Q10. [Application] A table named Employee has a DepartmentID column that references
Department(DepartmentID). A user attempts to delete a Department row that has matching Employee rows.
Which integrity rule is at risk of being violated?
A. Referential integrity — the foreign key in Employee would reference a non-existent Department row if
the parent row is deleted. SQL handles this via ON DELETE CASCADE, SET NULL, RESTRICT, or NO
ACTION. [CORRECT]
B. Domain integrity.
C. Key integrity.
Page 3
, WGU C170 Data Management Applications | 2026/2027 420 Questions & Verified Answers
D. Entity integrity.
Correct Answer: A
Rationale: Referential integrity requires that foreign key values match existing primary key values in the
referenced table or be NULL; deleting a parent row with existing child rows violates this unless the FK constraint
specifies CASCADE/SET NULL/SET DEFAULT. C170 Module 2 emphasizes referential integrity.
Q11. [Recall] Which type of key uniquely identifies each row in a table but is not chosen as the primary key?
A. Candidate key — a minimal set of attributes that uniquely identifies tuples; one is selected as the
primary key, the others become alternate keys. [CORRECT]
B. Surrogate key.
C. Foreign key.
D. Composite key.
Correct Answer: A
Rationale: A candidate key is a minimal unique identifier; one is chosen as PK, the others are alternate keys. A
composite key (C) is a multi-column key; a surrogate key (D) is an artificial identifier. C170 Module 2 covers key
types.
Q12. [Recall] Which key type is composed of two or more columns whose combination uniquely identifies a
row?
A. Composite key — multiple columns whose combined values uniquely identify each tuple (e.g., OrderID
+ ProductID in an order-line table). [CORRECT]
B. Surrogate key.
C. Foreign key.
D. Alternate key.
Correct Answer: A
Rationale: A composite key combines two or more columns to uniquely identify a tuple; common in junction
(associative) tables for many-to-many relationships. C170 Module 2 includes composite key definitions.
Q13. [Recall] Which key is an artificial, system-generated unique identifier with no business meaning?
A. Composite key.
B. Natural key.
C. Surrogate key — an artificial identifier (often an auto-increment integer or UUID) with no business
meaning; preferred when natural keys are unstable, complex, or sensitive. [CORRECT]
D. Foreign key.
Correct Answer: C
Rationale: A surrogate key is an artificial identifier (auto-increment, UUID) with no business meaning; preferred
when natural keys (SSN, email) are unstable, complex, or sensitive. C170 Module 2 contrasts natural vs. surrogate
keys.
Q14. [Recall] Which ANSI/ISO SQL standard introduced window functions (OVER clause), MERGE
statements, and XML support, forming the foundation for most modern RDBMS features?
A. SQL:1999 (SQL3) — introduced window functions, MERGE, recursive queries (WITH), and XML
support; subsequent standards (SQL:2003, 2006, 2008, 2011, 2016, 2019, 2023) added JSON,
polymorphic tables, and property graphs. [CORRECT]
B. SQL-92 only.
C. SQL-86.
D. SQL-89.
Correct Answer: A
Page 4
