WGU C792 TASK 2 ENTITY RELATIONSHIP DIAGRAM ERD
REFLECTION 2026/2027 | Update with Complete Solutions
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Section 1: Database Fundamentals & ERD Concepts (Questions
1-15)
Question 1
Which term describes an organized collection of structured data stored electronically
that supports efficient retrieval, manipulation, and management?
A. Data warehouse
B. Database [CORRECT]
C. Spreadsheet
D. File system
Rationale: A database is an organized collection of structured data stored
electronically with defined schemas, relationships, and query capabilities. Data
warehouses (A) are specialized for analytics. Spreadsheets (C) lack relational structure
and integrity controls. File systems (D) store unstructured data. WGU C792
emphasizes that databases provide data integrity, concurrency control, and
security—essential for healthcare applications where accuracy and confidentiality are
critical.
Correct Answer: B
Question 2
Which database model organizes data into tables with rows representing records and
columns representing attributes?
,A. Hierarchical database
B. Network database
C. Relational database [CORRECT]
D. NoSQL database
Rationale: Relational databases (RDBMS) organize data into tables (relations) with
rows (tuples/records) and columns (attributes/fields), using SQL for manipulation.
Hierarchical (A) uses tree structures. Network (B) uses graph structures. NoSQL (D)
uses document, key-value, or graph models. WGU C792 emphasizes that relational
models dominate healthcare due to ACID properties (Atomicity, Consistency,
Isolation, Durability) ensuring transaction integrity for patient safety-critical
operations.
Correct Answer: C
Question 3
Which constraint ensures that each record in a table has a unique identifier that
cannot be null?
A. Foreign key
B. Unique constraint
C. Primary key [CORRECT]
D. Check constraint
Rationale: A primary key uniquely identifies each record in a table, enforcing entity
integrity through two rules: NOT NULL (every record must have a value) and UNIQUE
(no duplicate values). Foreign keys (A) establish relationships. Unique constraints (B)
allow nulls. Check constraints (D) validate data ranges. WGU C792 emphasizes that
primary keys are foundational; in healthcare, Medical Record Numbers (MRN) or
surrogate keys ensure each patient encounter is uniquely identifiable across systems.
Correct Answer: C
,Question 4
Which attribute in one table establishes a relationship by referencing the primary key
of another table?
A. Primary key
B. Candidate key
C. Foreign key [CORRECT]
D. Surrogate key
Rationale: A foreign key creates referential integrity between tables by referencing a
primary key in another table (e.g., PatientID in Encounter table references PatientID in
Patient table). It enables joins and enforces relationship constraints. Primary keys (A)
identify records within their own table. Candidate keys (B) could be primary keys.
Surrogate keys (D) are artificial identifiers. WGU C792 emphasizes that foreign keys
are essential for relational database design; without them, data becomes fragmented
and relationships are lost.
Correct Answer: C
Question 5
Which primary key consists of two or more attributes combined to uniquely identify
a record?
A. Surrogate key
B. Natural key
C. Composite key [CORRECT]
D. Candidate key
Rationale: A composite key combines multiple attributes to achieve uniqueness
when no single attribute suffices (e.g., EncounterID + LineItemNumber for encounter
charges; CourseID + StudentID for enrollments). Surrogate keys (A) are single
, artificial identifiers. Natural keys (B) derive from business data. Candidate keys (D) are
potential primary keys. WGU C792 emphasizes that composite keys are common in
healthcare junction tables (patient-allergy, encounter-diagnosis) where the
combination of two foreign keys creates uniqueness.
Correct Answer: C
Question 6
Which attribute(s) could potentially serve as the primary key for an entity?
A. Foreign key
B. Composite key
C. Candidate key [CORRECT]
D. Surrogate key
Rationale: A candidate key is any attribute or combination that could uniquely
identify records (satisfies uniqueness and minimality). The primary key is selected
from candidate keys. An entity may have multiple candidate keys (e.g., Patient table:
MRN, SSN, or Email could each be unique). Foreign keys (A) reference other tables.
Composite (B) and surrogate (D) are types of keys, not the general concept. WGU
C792 emphasizes that choosing the best candidate key involves evaluating stability,
simplicity, and business meaning.
Correct Answer: C
Question 7
Which type of key is an artificial identifier (e.g., auto-increment integer, GUID) with
no business meaning, generated solely for database purposes?
A. Natural key
B. Composite key
REFLECTION 2026/2027 | Update with Complete Solutions
| Pass Guaranteed - A+ Graded
Section 1: Database Fundamentals & ERD Concepts (Questions
1-15)
Question 1
Which term describes an organized collection of structured data stored electronically
that supports efficient retrieval, manipulation, and management?
A. Data warehouse
B. Database [CORRECT]
C. Spreadsheet
D. File system
Rationale: A database is an organized collection of structured data stored
electronically with defined schemas, relationships, and query capabilities. Data
warehouses (A) are specialized for analytics. Spreadsheets (C) lack relational structure
and integrity controls. File systems (D) store unstructured data. WGU C792
emphasizes that databases provide data integrity, concurrency control, and
security—essential for healthcare applications where accuracy and confidentiality are
critical.
Correct Answer: B
Question 2
Which database model organizes data into tables with rows representing records and
columns representing attributes?
,A. Hierarchical database
B. Network database
C. Relational database [CORRECT]
D. NoSQL database
Rationale: Relational databases (RDBMS) organize data into tables (relations) with
rows (tuples/records) and columns (attributes/fields), using SQL for manipulation.
Hierarchical (A) uses tree structures. Network (B) uses graph structures. NoSQL (D)
uses document, key-value, or graph models. WGU C792 emphasizes that relational
models dominate healthcare due to ACID properties (Atomicity, Consistency,
Isolation, Durability) ensuring transaction integrity for patient safety-critical
operations.
Correct Answer: C
Question 3
Which constraint ensures that each record in a table has a unique identifier that
cannot be null?
A. Foreign key
B. Unique constraint
C. Primary key [CORRECT]
D. Check constraint
Rationale: A primary key uniquely identifies each record in a table, enforcing entity
integrity through two rules: NOT NULL (every record must have a value) and UNIQUE
(no duplicate values). Foreign keys (A) establish relationships. Unique constraints (B)
allow nulls. Check constraints (D) validate data ranges. WGU C792 emphasizes that
primary keys are foundational; in healthcare, Medical Record Numbers (MRN) or
surrogate keys ensure each patient encounter is uniquely identifiable across systems.
Correct Answer: C
,Question 4
Which attribute in one table establishes a relationship by referencing the primary key
of another table?
A. Primary key
B. Candidate key
C. Foreign key [CORRECT]
D. Surrogate key
Rationale: A foreign key creates referential integrity between tables by referencing a
primary key in another table (e.g., PatientID in Encounter table references PatientID in
Patient table). It enables joins and enforces relationship constraints. Primary keys (A)
identify records within their own table. Candidate keys (B) could be primary keys.
Surrogate keys (D) are artificial identifiers. WGU C792 emphasizes that foreign keys
are essential for relational database design; without them, data becomes fragmented
and relationships are lost.
Correct Answer: C
Question 5
Which primary key consists of two or more attributes combined to uniquely identify
a record?
A. Surrogate key
B. Natural key
C. Composite key [CORRECT]
D. Candidate key
Rationale: A composite key combines multiple attributes to achieve uniqueness
when no single attribute suffices (e.g., EncounterID + LineItemNumber for encounter
charges; CourseID + StudentID for enrollments). Surrogate keys (A) are single
, artificial identifiers. Natural keys (B) derive from business data. Candidate keys (D) are
potential primary keys. WGU C792 emphasizes that composite keys are common in
healthcare junction tables (patient-allergy, encounter-diagnosis) where the
combination of two foreign keys creates uniqueness.
Correct Answer: C
Question 6
Which attribute(s) could potentially serve as the primary key for an entity?
A. Foreign key
B. Composite key
C. Candidate key [CORRECT]
D. Surrogate key
Rationale: A candidate key is any attribute or combination that could uniquely
identify records (satisfies uniqueness and minimality). The primary key is selected
from candidate keys. An entity may have multiple candidate keys (e.g., Patient table:
MRN, SSN, or Email could each be unique). Foreign keys (A) reference other tables.
Composite (B) and surrogate (D) are types of keys, not the general concept. WGU
C792 emphasizes that choosing the best candidate key involves evaluating stability,
simplicity, and business meaning.
Correct Answer: C
Question 7
Which type of key is an artificial identifier (e.g., auto-increment integer, GUID) with
no business meaning, generated solely for database purposes?
A. Natural key
B. Composite key
