WGU D426 V2 MIDTERM EXAM 2026 QUESTIONS WITH ANSWERS GRADED A+

WGU D426 V2 MIDTERM EXAM 2026
QUESTIONS WITH ANSWERS GRADED A+


◉ tuple (Relational Model). Answer: an ordered collection of elements
enclosed in parentheses. Ex: (a, b, c) and (c, b, a) are different, since
tuples are ordered.


◉ Rules (Relational Model). Answer: that govern valid data


◉ table (Relational Model). Answer: has a name, a fixed tuple of
columns, and a varying set of rows.


◉ column (Relational Model). Answer: has a name and a data type.


◉ row (Relational Model). Answer: an unnamed tuple of values. Each
value corresponds to a column and belongs to the column's data type.


◉ data type (Relational Model). Answer: a named set of values, from
which column values are drawn.


◉ Select (Relational Model). Answer: selects a subset of rows of a table.
(Relational operations)

, ◉ Join (Relational Model). Answer: combines two tables by comparing
related columns. (Relational operations)


◉ Union (Relational Model). Answer: selects all rows of two tables
(Relational operations)


◉ Aggregate (Relational Model). Answer: perform a calculation on a set
of values and return a single result. They are commonly used to
summarize or analyze data, such as calculating sums, averages, counts,
or finding maximum or minimum values within a dataset. (Relational
operations)


◉ logical constraints (Relational Model). Answer: Rules that ensure data
is valid (Relational Rules)


◉ Business rules (Relational Model). Answer: e based on business
policy and specific to a particular database.


Ex: PassportNumber values may not repeat in different Employee rows.


◉ Structured Query Language (SQL). Answer: the standard language for
relational databases, and is commonly supported in non-relational
databases.