WGU c170 Exam Review Questions with Correct
Answers
named section of permanent storage space that is reserved to store the database
Area
Also known as composite entity
Associative Entity
Another name for a composite entity
Bridge Entity
A minimal superkey; that is, a key that does not contain a subset of attributes that is
itself a superkey.
candidate key
A property of relational operators that permits the use of relational algebra operators
on existing tables (relations) to produce new relations.
closure
An entity designed to transform an M:N relationship into two 1:M relationships. The
composite entity's primary key comprises at least the primary keys of the entities that it
connects. Also known as a bridge entity. See also linking table.
composite entity
A multiple attribute key
composite key
An attribute whose value is determined by another attribute.
,dependent
The role of a key. In the context of a database table, the statement "A determines B"
indicates that knowing the value of attribute A means that the value of attribute B can
be looked up.
determination
In relational algebra, an operator used to yield all rows from one table that are not
found in another union-compatible table.
DIFFERENCE
In relational algebra, an operator that answers queries about one set of data being
associated with all values of data in another set of data.
DIVIDE
In data modeling, the construct used to organize and describe an attributes set of
possible values.
domain
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.
entity integrity
A join operator that links tables based on an equality condition that compares specified
columns of the tables.
equijoin
, 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.
flags
An attribute or attributes in one table whose values must match the primary key in
another table or whose values must be null.
foreign key (FK)
A condition in which an attribute is functionally dependent on a composite key but not
on any subset of the key.
full functional dependence
Within a relation R, an attribute B is functionally dependent on an attribute A if and
only if a given value of the attribute A determines exactly one value of the attribute B.
The relationship "B is dependent on A" is equivalent to "A determines B" and is
written as A B.
functional dependence
The use of the same name to label different attributes. Homonyms should be avoided in
databases
homonyms
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
Also called an index.
Answers
named section of permanent storage space that is reserved to store the database
Area
Also known as composite entity
Associative Entity
Another name for a composite entity
Bridge Entity
A minimal superkey; that is, a key that does not contain a subset of attributes that is
itself a superkey.
candidate key
A property of relational operators that permits the use of relational algebra operators
on existing tables (relations) to produce new relations.
closure
An entity designed to transform an M:N relationship into two 1:M relationships. The
composite entity's primary key comprises at least the primary keys of the entities that it
connects. Also known as a bridge entity. See also linking table.
composite entity
A multiple attribute key
composite key
An attribute whose value is determined by another attribute.
,dependent
The role of a key. In the context of a database table, the statement "A determines B"
indicates that knowing the value of attribute A means that the value of attribute B can
be looked up.
determination
In relational algebra, an operator used to yield all rows from one table that are not
found in another union-compatible table.
DIFFERENCE
In relational algebra, an operator that answers queries about one set of data being
associated with all values of data in another set of data.
DIVIDE
In data modeling, the construct used to organize and describe an attributes set of
possible values.
domain
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.
entity integrity
A join operator that links tables based on an equality condition that compares specified
columns of the tables.
equijoin
, 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.
flags
An attribute or attributes in one table whose values must match the primary key in
another table or whose values must be null.
foreign key (FK)
A condition in which an attribute is functionally dependent on a composite key but not
on any subset of the key.
full functional dependence
Within a relation R, an attribute B is functionally dependent on an attribute A if and
only if a given value of the attribute A determines exactly one value of the attribute B.
The relationship "B is dependent on A" is equivalent to "A determines B" and is
written as A B.
functional dependence
The use of the same name to label different attributes. Homonyms should be avoided in
databases
homonyms
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
Also called an index.
