WGU D426 Data Management Foundations New Pre-
Assessment Latest Update 2026 | Exam Prep | 100%
Accurate Answers
1. Describe what constitutes an expression in SQL and provide an example.
An expression in SQL is a combination of values, operators, and
functions that evaluates to a value; for example, City = 'Beijing'.
An expression can only be a SQL command like SELECT.
An expression is a string literal like 'Welcome'.
An expression is only a numerical value like 134.
2. For the relationship represented in the figure below, which of the following is
true?
An address can be unassigned to a customer
A customer must have at least one address.
A customer can have many addresses but does not have to have an
address.
, An address can belong to more than one customer.
3. What is the relationship between the columns appearing in a SELECT clause
and columns in a GROUP BY clause?
The SELECT clause may have additional non aggregate columns not
appearing in the GROUP BY clause. lse
The non aggregate columns in the SELECT clause must match the
columns in the GROUP BY clause.
The GROUP BY clause may have additional columns not in the SELECT
clause.
SELECT and GROUP BY clauses are independent so no relationship.
4. What is the appropriate data type for storing geographical coordinates in a
database?
Integer
Decimal
Text
Spatial
5. POLYGON, POINT, and GEOMETRY are what kind of data types?
Character
Document
Spatial
Time
6. What is an attribute in a data model?
None of the above.
A characteristic of an entity.
, A software that helps users create databases.
A relationship between two entities.
7. Describe the difference between a dense index and a sparse index in
database management.
A dense index is created automatically, while a sparse index must be
created manually.
A dense index is faster than a sparse index in all cases.
A dense index contains an entry for every record, while a sparse
index only includes entries for some records.
A dense index is used for text data, while a sparse index is used for
numeric data.
8. Describe how the '%' wildcard character functions within the context of the
LIKE operator in SQL.
The '%' wildcard character is used to denote the beginning of a string.
The '%' wildcard character allows for matching any sequence of
characters, including none, in a string comparison using the LIKE
operator.
The '%' wildcard character is only applicable in SELECT statements.
The '%' wildcard character is used to match exactly one character in a
string comparison.
9. Which columns can be compared in a join?
any columns
only columns with compatible data types
only primary and foreign key columns
10. Describe the implications of including a non-aggregated column in the
, SELECT clause without it being part of the GROUP BY clause.
The query will run successfully and return random values for that
column.
It will ignore the non-aggregated column and only return
aggregated results.
Including a non-aggregated column in the SELECT clause without it
being part of the GROUP BY clause will lead to an error because
SQL cannot determine which value to display for that column.
It will automatically select the first value of that column for each
group.
11. What is the purpose of the ON DELETE RESTRICT clause in a foreign key
definition?
To set referenced rows to a default value
To set referenced rows to NULL
To prevent deletion of referenced rows
To delete all related rows
12. What is the term used to describe a join that does not use equality between
columns?
non-equijoin
cross join
natural join
self join
13. Describe how set theory contributes to the organization of data in relational
databases.
Assessment Latest Update 2026 | Exam Prep | 100%
Accurate Answers
1. Describe what constitutes an expression in SQL and provide an example.
An expression in SQL is a combination of values, operators, and
functions that evaluates to a value; for example, City = 'Beijing'.
An expression can only be a SQL command like SELECT.
An expression is a string literal like 'Welcome'.
An expression is only a numerical value like 134.
2. For the relationship represented in the figure below, which of the following is
true?
An address can be unassigned to a customer
A customer must have at least one address.
A customer can have many addresses but does not have to have an
address.
, An address can belong to more than one customer.
3. What is the relationship between the columns appearing in a SELECT clause
and columns in a GROUP BY clause?
The SELECT clause may have additional non aggregate columns not
appearing in the GROUP BY clause. lse
The non aggregate columns in the SELECT clause must match the
columns in the GROUP BY clause.
The GROUP BY clause may have additional columns not in the SELECT
clause.
SELECT and GROUP BY clauses are independent so no relationship.
4. What is the appropriate data type for storing geographical coordinates in a
database?
Integer
Decimal
Text
Spatial
5. POLYGON, POINT, and GEOMETRY are what kind of data types?
Character
Document
Spatial
Time
6. What is an attribute in a data model?
None of the above.
A characteristic of an entity.
, A software that helps users create databases.
A relationship between two entities.
7. Describe the difference between a dense index and a sparse index in
database management.
A dense index is created automatically, while a sparse index must be
created manually.
A dense index is faster than a sparse index in all cases.
A dense index contains an entry for every record, while a sparse
index only includes entries for some records.
A dense index is used for text data, while a sparse index is used for
numeric data.
8. Describe how the '%' wildcard character functions within the context of the
LIKE operator in SQL.
The '%' wildcard character is used to denote the beginning of a string.
The '%' wildcard character allows for matching any sequence of
characters, including none, in a string comparison using the LIKE
operator.
The '%' wildcard character is only applicable in SELECT statements.
The '%' wildcard character is used to match exactly one character in a
string comparison.
9. Which columns can be compared in a join?
any columns
only columns with compatible data types
only primary and foreign key columns
10. Describe the implications of including a non-aggregated column in the
, SELECT clause without it being part of the GROUP BY clause.
The query will run successfully and return random values for that
column.
It will ignore the non-aggregated column and only return
aggregated results.
Including a non-aggregated column in the SELECT clause without it
being part of the GROUP BY clause will lead to an error because
SQL cannot determine which value to display for that column.
It will automatically select the first value of that column for each
group.
11. What is the purpose of the ON DELETE RESTRICT clause in a foreign key
definition?
To set referenced rows to a default value
To set referenced rows to NULL
To prevent deletion of referenced rows
To delete all related rows
12. What is the term used to describe a join that does not use equality between
columns?
non-equijoin
cross join
natural join
self join
13. Describe how set theory contributes to the organization of data in relational
databases.
