D427 / D 427 Final Exam (Latest Update
) Data Management –
Applications | Questions and Answers | Grade
A | 100% Correct (Verified Answers) - WGU
Database Concepts and Models (Questions 1–20)
1. What are the three components of a database model?
Answer: Data structures, operations, and rules
Rationale: A database model defines how data is organized, manipulated, and validated.
Data structures prescribe organization, operations manipulate data, and rules ensure valid
data.
2. What is the relational model?
Answer: A database model based on a tabular data structure
Rationale: Published by E.F. Codd in 1970, the relational model uses tables (relations)
with standardized SQL operations. It’s widely used in applications like banking and
airline systems.
3. What characterizes big data?
Answer: Unprecedented data volumes and rapidly changing data structures
Rationale: Big data, driven by internet growth since the 1990s, involves large-scale,
dynamic datasets that challenge traditional database systems.
4. What is a set in database terminology?
Answer: An unordered collection of elements enclosed in braces
Rationale: Sets, like {a, b, c}, have no specific order, distinguishing them from ordered
structures like tuples.
5. What is a tuple?
Answer: An ordered collection of elements enclosed in parentheses
Rationale: Tuples, like (a, b, c), maintain a specific order, unlike sets, and are used to
represent rows in a table.
6. What defines a table in a relational database?
Answer: A named structure with a fixed tuple of columns and a varying set of rows
Rationale: Tables have a defined schema (columns) and dynamic content (rows),
adhering to relational model principles.
7. What is a column in a database table?
Answer: A named attribute with a specific data type
Rationale: Columns define the structure of a table, each associated with a data type that
constrains the values it can hold.
8. What is a row in a database table?
Answer: An unnamed tuple of values corresponding to columns
, Rationale: Rows represent individual records, with each value adhering to the data type
of its respective column.
9. What is a data type in a database?
Answer: A named set of values from which column values are drawn
Rationale: Data types (e.g., INT, VARCHAR) define the permissible values for a
column, ensuring data consistency.
10. What is relational algebra?
Answer: A collection of operations forming the theoretical foundation of SQL
Rationale: Relational algebra provides operations like Select, Project, and Join, which
SQL implements to manipulate tables.
11. What are relational rules?
Answer: Constraints enforced by the database system to govern data
Rationale: Relational rules, implemented as SQL constraints, ensure data integrity, such
as unique primary keys and no duplicate rows.
12. What are three key relational rules?
Answer: Unique primary keys, unique column names, no duplicate rows
Rationale: These rules ensure data integrity and consistency in relational databases,
preventing ambiguity and redundancy.
13. What are business rules in a database?
Answer: Rules based on business policy specific to a particular database
Rationale: Unlike relational rules, business rules reflect organizational policies, such as
specific data validation requirements.
14. What is a primary key?
Answer: A column that uniquely identifies each row in a table
Rationale: Primary keys ensure each record is distinct, facilitating data retrieval and
integrity.
15. What is a foreign key?
Answer: A column that references the primary key of another table
Rationale: Foreign keys enforce referential integrity, linking related data across tables.
16. What is a strong entity in ER modeling?
Answer: An entity with a unique identifying attribute
Rationale: Strong entities have primary keys and do not depend on other entities for
identification.
17. What symbol represents a one-to-many relationship in ER diagrams?
Answer: A crow’s foot
Rationale: In ER diagrams, a crow’s foot indicates that one record in a table can relate to
multiple records in another.
18. What is a heap table?
Answer: A table with no specific order imposed on rows
Rationale: Heap tables store rows as they are inserted, without indexing or sorting,
unlike clustered tables.
19. What describes a one-to-one relationship in ER modeling, such as a salesperson and
an office space?
Answer: One-to-one
Rationale: Each salesperson is assigned exactly one office, and each office is assigned to
one salesperson, defining a one-to-one relationship.
) Data Management –
Applications | Questions and Answers | Grade
A | 100% Correct (Verified Answers) - WGU
Database Concepts and Models (Questions 1–20)
1. What are the three components of a database model?
Answer: Data structures, operations, and rules
Rationale: A database model defines how data is organized, manipulated, and validated.
Data structures prescribe organization, operations manipulate data, and rules ensure valid
data.
2. What is the relational model?
Answer: A database model based on a tabular data structure
Rationale: Published by E.F. Codd in 1970, the relational model uses tables (relations)
with standardized SQL operations. It’s widely used in applications like banking and
airline systems.
3. What characterizes big data?
Answer: Unprecedented data volumes and rapidly changing data structures
Rationale: Big data, driven by internet growth since the 1990s, involves large-scale,
dynamic datasets that challenge traditional database systems.
4. What is a set in database terminology?
Answer: An unordered collection of elements enclosed in braces
Rationale: Sets, like {a, b, c}, have no specific order, distinguishing them from ordered
structures like tuples.
5. What is a tuple?
Answer: An ordered collection of elements enclosed in parentheses
Rationale: Tuples, like (a, b, c), maintain a specific order, unlike sets, and are used to
represent rows in a table.
6. What defines a table in a relational database?
Answer: A named structure with a fixed tuple of columns and a varying set of rows
Rationale: Tables have a defined schema (columns) and dynamic content (rows),
adhering to relational model principles.
7. What is a column in a database table?
Answer: A named attribute with a specific data type
Rationale: Columns define the structure of a table, each associated with a data type that
constrains the values it can hold.
8. What is a row in a database table?
Answer: An unnamed tuple of values corresponding to columns
, Rationale: Rows represent individual records, with each value adhering to the data type
of its respective column.
9. What is a data type in a database?
Answer: A named set of values from which column values are drawn
Rationale: Data types (e.g., INT, VARCHAR) define the permissible values for a
column, ensuring data consistency.
10. What is relational algebra?
Answer: A collection of operations forming the theoretical foundation of SQL
Rationale: Relational algebra provides operations like Select, Project, and Join, which
SQL implements to manipulate tables.
11. What are relational rules?
Answer: Constraints enforced by the database system to govern data
Rationale: Relational rules, implemented as SQL constraints, ensure data integrity, such
as unique primary keys and no duplicate rows.
12. What are three key relational rules?
Answer: Unique primary keys, unique column names, no duplicate rows
Rationale: These rules ensure data integrity and consistency in relational databases,
preventing ambiguity and redundancy.
13. What are business rules in a database?
Answer: Rules based on business policy specific to a particular database
Rationale: Unlike relational rules, business rules reflect organizational policies, such as
specific data validation requirements.
14. What is a primary key?
Answer: A column that uniquely identifies each row in a table
Rationale: Primary keys ensure each record is distinct, facilitating data retrieval and
integrity.
15. What is a foreign key?
Answer: A column that references the primary key of another table
Rationale: Foreign keys enforce referential integrity, linking related data across tables.
16. What is a strong entity in ER modeling?
Answer: An entity with a unique identifying attribute
Rationale: Strong entities have primary keys and do not depend on other entities for
identification.
17. What symbol represents a one-to-many relationship in ER diagrams?
Answer: A crow’s foot
Rationale: In ER diagrams, a crow’s foot indicates that one record in a table can relate to
multiple records in another.
18. What is a heap table?
Answer: A table with no specific order imposed on rows
Rationale: Heap tables store rows as they are inserted, without indexing or sorting,
unlike clustered tables.
19. What describes a one-to-one relationship in ER modeling, such as a salesperson and
an office space?
Answer: One-to-one
Rationale: Each salesperson is assigned exactly one office, and each office is assigned to
one salesperson, defining a one-to-one relationship.
