WGU C175/D426 DATA MANAGEMENT
FOUNDATIONS OA EXAM PRACTICE
QUESTIONS WITH CORRECT DETAILED
ANSWERS
Version A - Questions 1-50
Question 1
What does cardinality refer to in an ER diagram and how
does it appear?
Answer: Cardinality refers to the MAXIMUM number of
times an instance in one entity can be associated with an
instance of another entity (maxima). It appears as a 1 or M on
the relationship line, closest to the entity.
Rationale: Cardinality defines the maximum participation in a
relationship. The "1" indicates at most one occurrence, while
"M" (or "N") indicates many occurrences. This is distinct from
modality, which specifies minimum participation.
Question 2
,What does modality refer to in an ER diagram and how
does it appear?
Answer: Modality refers to the MINIMUM number of times
an instance in one entity can be associated with an instance of
another entity (minima). It appears as a 0 or 1 on the
relationship line, next to cardinality.
Rationale: Modality specifies whether participation is optional
(0) or mandatory (1). Together with cardinality, it defines the
complete relationship constraints. If modality is 0, the
entity's participation is optional; if 1, participation is
required.
Question 3
Which constraint propagates primary key changes to
foreign keys?
Answer: CASCADE
Rationale: The CASCADE constraint ensures that updates or
deletions in the primary key table automatically reflect in the
foreign key table. When a primary key value changes,
CASCADE updates all matching foreign key values. When a
primary key row is deleted, CASCADE deletes all related
,foreign key rows. This maintains referential integrity without
manual intervention.
Question 4
What is shown on the "many" side of a relationship
between two tables?
Answer: Foreign key
Rationale: In a one-to-many (1:M) relationship, the foreign
key is placed in the table on the "many" side to establish the
relationship with the primary key of the "one" side. For
example, in a Departments-Employees relationship, DeptID
would appear as a foreign key in the Employees table (the
many side).
Question 5
Which designation is an individual value, such as a salary?
Answer: Attribute type
Rationale: An attribute type refers to a single, specific value
within a table, such as Salary, Age, or Price. It represents
individual data elements that describe an entity. Entity types
, represent classes of objects, relationships define connections
between entities, and glossaries are documentation.
Question 6
Which type of join selects all rows from both the left and
right table, regardless of match?
Answer: FULL JOIN (FULL OUTER JOIN)
Rationale: A FULL OUTER JOIN selects all records from
both tables, filling in NULL values where there is no match.
This ensures no data is lost from either table. LEFT JOIN
includes all rows from left table only, RIGHT JOIN includes
all rows from right table only, and CROSS JOIN produces a
Cartesian product.
Question 7
Which function measures a numeric value's distance from
0?
Answer: ABS() (absolute value)
Rationale: The ABS() function in SQL returns the absolute
value of a given number, effectively measuring its distance
from zero. It always returns a non-negative value. Other
FOUNDATIONS OA EXAM PRACTICE
QUESTIONS WITH CORRECT DETAILED
ANSWERS
Version A - Questions 1-50
Question 1
What does cardinality refer to in an ER diagram and how
does it appear?
Answer: Cardinality refers to the MAXIMUM number of
times an instance in one entity can be associated with an
instance of another entity (maxima). It appears as a 1 or M on
the relationship line, closest to the entity.
Rationale: Cardinality defines the maximum participation in a
relationship. The "1" indicates at most one occurrence, while
"M" (or "N") indicates many occurrences. This is distinct from
modality, which specifies minimum participation.
Question 2
,What does modality refer to in an ER diagram and how
does it appear?
Answer: Modality refers to the MINIMUM number of times
an instance in one entity can be associated with an instance of
another entity (minima). It appears as a 0 or 1 on the
relationship line, next to cardinality.
Rationale: Modality specifies whether participation is optional
(0) or mandatory (1). Together with cardinality, it defines the
complete relationship constraints. If modality is 0, the
entity's participation is optional; if 1, participation is
required.
Question 3
Which constraint propagates primary key changes to
foreign keys?
Answer: CASCADE
Rationale: The CASCADE constraint ensures that updates or
deletions in the primary key table automatically reflect in the
foreign key table. When a primary key value changes,
CASCADE updates all matching foreign key values. When a
primary key row is deleted, CASCADE deletes all related
,foreign key rows. This maintains referential integrity without
manual intervention.
Question 4
What is shown on the "many" side of a relationship
between two tables?
Answer: Foreign key
Rationale: In a one-to-many (1:M) relationship, the foreign
key is placed in the table on the "many" side to establish the
relationship with the primary key of the "one" side. For
example, in a Departments-Employees relationship, DeptID
would appear as a foreign key in the Employees table (the
many side).
Question 5
Which designation is an individual value, such as a salary?
Answer: Attribute type
Rationale: An attribute type refers to a single, specific value
within a table, such as Salary, Age, or Price. It represents
individual data elements that describe an entity. Entity types
, represent classes of objects, relationships define connections
between entities, and glossaries are documentation.
Question 6
Which type of join selects all rows from both the left and
right table, regardless of match?
Answer: FULL JOIN (FULL OUTER JOIN)
Rationale: A FULL OUTER JOIN selects all records from
both tables, filling in NULL values where there is no match.
This ensures no data is lost from either table. LEFT JOIN
includes all rows from left table only, RIGHT JOIN includes
all rows from right table only, and CROSS JOIN produces a
Cartesian product.
Question 7
Which function measures a numeric value's distance from
0?
Answer: ABS() (absolute value)
Rationale: The ABS() function in SQL returns the absolute
value of a given number, effectively measuring its distance
from zero. It always returns a non-negative value. Other
