WGU D427 Data Management Applications OA Exam 2025/2026 – 150 Verified Questions with Well-Explained Answers | A+ Grade | Latest Update

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WGU D427 Data Management
Applications OA Exam 2025/2026 – 150
Verified Questions with Well-Explained
Answers | A+ Grade | Latest Update

Entity-Relationship Diagrams (ERDs) (25 Questions)

Question 1
What does an Entity-Relationship Diagram (ERD) primarily represent?
A) Database storage capacity
B) Relationships between entities
C) SQL query execution plans
D) Data encryption methods
Rationale: An ERD visually represents entities, their attributes, and the relationships between
them in a database, forming the basis for relational database design.

Question 2
In an ERD, what symbol represents a relationship between two entities?
A) Rectangle
B) Oval
C) Diamond
D) Line
Rationale: In ERDs, a diamond symbol is used to denote relationships between entities,
connecting them to show how they interact.

Question 3
Which component of an ERD represents a table in a relational database?
A) Attribute
B) Entity
C) Relationship
D) Primary key
Rationale: Entities in an ERD correspond to tables in a relational database, with each entity
containing attributes that become columns.

Question 4
What does a crow’s foot notation in an ERD indicate?
A) One-to-one relationship
B) One-to-many relationship
C) Many-to-many relationship
D) No relationship

, 2


Rationale: Crow’s foot notation indicates a one-to-many relationship, where one record in one
entity can be related to multiple records in another.

Question 5
Which ERD component represents a unique identifier for an entity?
A) Relationship
B) Attribute
C) Primary key
D) Foreign key
Rationale: A primary key uniquely identifies each record in an entity, ensuring no duplicates
and enabling relationships.

Question 6
In an ERD, how is a many-to-many relationship typically resolved?
A) Using a single foreign key
B) Creating a junction table
C) Adding a composite key
D) Removing the relationship
Rationale: A many-to-many relationship is resolved by creating a junction table that contains
foreign keys from both related entities.

Question 7
What does a double line connecting an entity to a relationship in an ERD signify?
A) Optional participation
B) Mandatory participation
C) Weak entity
D) Composite key
Rationale: A double line indicates that the entity’s participation in the relationship is mandatory,
meaning every instance must be related.

Question 8
Which type of key in an ERD links two tables together?
A) Primary key
B) Foreign key
C) Candidate key
D) Alternate key
Rationale: A foreign key in one table references the primary key of another, establishing a
relationship between them.

Question 9
What does a weak entity in an ERD depend on?
A) A foreign key
B) A strong entity
C) A composite key
D) A relationship diamond

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Rationale: A weak entity lacks a unique identifier and depends on a strong entity for its
existence, often linked via a foreign key.

Question 10
In an ERD, what does cardinality describe?
A) The number of attributes in an entity
B) The number of instances in a relationship
C) The data type of a column
D) The size of the database
Rationale: Cardinality specifies how many instances of one entity can be associated with
another in a relationship (e.g., one-to-many).

Question 11
Which ERD symbol represents an attribute?
A) Rectangle
B) Oval
C) Diamond
D) Line
Rationale: Attributes, which become columns in a table, are represented by ovals connected to
their respective entities in an ERD.

Question 12
What is the purpose of a composite key in an ERD?
A) To store multiple data types
B) To uniquely identify records using multiple attributes
C) To link unrelated tables
D) To enforce data integrity
Rationale: A composite key combines two or more attributes to create a unique identifier for
records in a table.

Question 13
Which relationship type in an ERD allows one record to be related to exactly one record in
another entity?
A) Many-to-many
B) One-to-one
C) One-to-many
D) Many-to-one
Rationale: A one-to-one relationship means each record in one entity is associated with exactly
one record in another.

Question 14
What does a dashed line in an ERD typically represent?
A) A strong entity
B) A weak entity relationship
C) A primary key
D) A mandatory relationship

, 4


Rationale: A dashed line indicates a relationship involving a weak entity, which depends on a
strong entity for identification.

Question 15
Which ERD component ensures referential integrity?
A) Attribute
B) Foreign key
C) Relationship
D) Entity
Rationale: Foreign keys enforce referential integrity by ensuring that values in one table match
valid primary key values in another.

Question 16
In an ERD, what does a single line connecting an entity to a relationship indicate?
A) Optional participation
B) Mandatory participation
C) A weak entity
D) A composite key
Rationale: A single line indicates that the entity’s participation in the relationship is optional,
meaning not all instances need to be related.

Question 17
What is the purpose of an ERD in database design?
A) To execute SQL queries
B) To model data structure and relationships
C) To optimize database performance
D) To encrypt sensitive data
Rationale: ERDs provide a visual blueprint for designing a database, showing entities, attributes,
and relationships.

Question 18
Which type of relationship in an ERD requires a junction table?
A) One-to-one
B) One-to-many
C) Many-to-many
D) Weak entity
Rationale: Many-to-many relationships are implemented using a junction table to store the
associations between entities.

Question 19
What does a primary key constraint in an ERD ensure?
A) Data encryption
B) Uniqueness of records
C) Optional relationships
D) Data compression