WGU C170 Focused on Chapter 1
Foundational Study Exam Questions with
Accurate Marking Scheme 2024/2025
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.
, index - correct answer An ordered array of index key values and row ID values
(pointers). Indexes are generally used to speed up and facilitate data retrieval. Also
known as an index key.
index key - correct answer See index.
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.
Foundational Study Exam Questions with
Accurate Marking Scheme 2024/2025
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.
, index - correct answer An ordered array of index key values and row ID values
(pointers). Indexes are generally used to speed up and facilitate data retrieval. Also
known as an index key.
index key - correct answer See index.
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.
