WGU C170 DATA MANAGEMENT
APPLICATION EXAM Q & A 2024
domain - correct answer In data modeling, the construct used to organize and describe an
attribute's set of possible values.
entity integrity - correct answer The property of a relational table that guarantees each entity
has a unique value in a primary key and that the key has no null values.
equijoin - correct answer A join operator that links tables based on an equality condition that
compares specified columns of the tables.
flags - correct answer Special codes implemented by designers to trigger a required response,
alert end users to specified conditions, or encode values. Flags may be used to prevent nulls by
bringing attention to the absence of a value in a table.
foreign key (FK) - correct answer An attribute or attributes in one table whose values must
match the primary key in another table or whose values must be null. See key.
full functional dependence - correct answer A condition in which an attribute is functionally
dependent on a composite key but not on any subset of the key.
functional dependence - correct answer Within a relation R, an attribute B is functionally
dependent on an attribute A if and only if a given value of attribute A determines exactly one
value of attribute B. The relationship "B is dependent on A" is equivalent to "A determines B,"
and is written as A->B.
homonyms - correct answer The use of the same name to label different attributes. Homonyms
generally should be avoided. Some relational software automatically checks for homonyms and
either alerts the user to their existence or automatically makes the appropriate adjustments.
See also synonym.
inner join - correct answer A join operation in which only rows that meet a given criterion are
selected. The join criterion can be an equality condition (natural join or equijoin) or an
inequality condition (theta join). The inner join is the most commonly used type of join.
Contrast with outer join.
INTERSECT - correct answer In relational algebra, an operator used to yield only the rows that
are common to two union-compatible tables.
JOIN - correct answer In relational algebra, a type of operator used to yield rows from two
tables based on criteria. There are many types of joins, such as natural join, theta join, equijoin,
and outer join.
join columns - correct answer Columns that are used in the criteria of join operations. The join
columns generally share similar values (have a compatible domain).
key - correct answer One or more attributes that determine other attributes. See also superkey,
candidate key, primary key (PK), secondary key, and foreign key.
key attribute - correct answer The attributes that form a primary key. See also prime attribute.
left outer join - correct answer In a pair of tables to be joined, a join that yields all the rows in
the left table, including those that have no matching values in the other table. For example, a
left outer join of CUSTOMER with AGENT will yield all of the CUSTOMER rows, including the
ones that do not have a matching AGENT row. See also outer join and right outer join.