Chapter 3

Question 0

A relation is a three-dimensional table

Answer 0

False

Question 1

All relations are tables, but not all tables are relations

Answer 1

True

Question 2

A characteristic of a relation is that the cells of the relation hold a single value

Answer 2

True

Question 3

A characteristic of a relation is that the rows of a relation may hold identical values

Answer 3

False

Question 4

A relation is a table composed of columns and rows

Answer 4

True

Question 5

In relational terms as defined by E.F. Codd, a row is called a tuple

Answer 5

True

Question 6

In relational terms as defined by E.F. Codd, a column is called an attribute

Answer 6

True

Question 7

The columns of a relation are sometimes called tuples

Answer 7

False

Question 8

A tuple is a group of one or more columns that uniquely identifies a row

Answer 8

False

Question 9

A functional dependency is a relationship between attributes such that if we know the value of one attribute, we can determine the value of the other attribute

Answer 9

True

Question 10

If by knowing the value of A we can find the value of B, then we can say that B is functionally dependent on A

Answer 10

True

Question 11

In functional dependencies, the attribute whose value is known or given is referred to as the determinant

Answer 11

True

Question 12

Attribute Y is functionally dependent on attributes X if the value of attribute X determines the value of Y

Answer 12

True

Question 13

The functional dependency noted as A -> B means that the value of A can be determined from the value or B

Answer 13

False

Question 14

In the functional dependency shown as A -> B, B is the determinant

Answer 14

False

Question 15

Functional dependencies can involve groups of attributes

Answer 15

True

Question 16

Given the functional dependency (A, B) -> C, the attributes (A,B) are referred to as a composite determinant

Answer 16

True

Question 17

Given the functional dependency A -> (B, C), then it is true that A -> B and A -> C

Answer 17

True

Question 18

Given the functional dependency (A, B) -> C, then it is true that A -> C and B -> C

Answer 18

False

Question 19

Given the functional dependency A -> B, then it is necessarily true that B -> A

Answer 19

False

Question 20

A determinant of a functional dependency may or may not be unique in a relation

Answer 20

True

Question 21

A key is a combination of one or more columns that is used to identify particular rows in a relation

Answer 21

True

Question 22

A row can be uniquely identified by a key

Answer 22

True

Question 23

A combination key is a group of attributes that uniquely identifies a row

Answer 23

False

Question 24

A key can be composed of a group of attributes taken together

Answer 24

True

Question 25

It is possible to have a relation that does not have a key

Answer 25

False

Question 26

A candidate key is one of the group keys that may serve as the primary key in a relation

Answer 26

True

Question 27

A relation can have only one candidate key

Answer 27

False

Question 28

A primary key is a candidate key that has been selected to uniquely identify rows in a relation

Answer 28

True

Question 29

A surrogate key is artificial column that is added to a relation to be its primary key

Answer 29

True

Question 30

A surrogate key usually slow performance

Answer 30

False

Question 31

Surrogate keys are normally not shown on forms or reports

Answer 31

True

Question 32

A foreign key is one or more columns in one relation that also is the primary key in another table

Answer 32

True

Question 33

A relation

Answer 33

Has rows containing data about an entity, has columns containing data about attributes of the entity, has cells that hold only a single value, has no two identical rows

Question 34

In a relation

Answer 34

The order of the rows is unimportant

Question 35

A relation is also known as a

Answer 35

Table

Question 36

A tuple is also know as a

Answer 36

Row

Question 37

An attribute is also known as a

Answer 37

Field

Question 38

Saying that two entities are functionally dependent means that

Answer 38

For one of the entities, if we are given the value of that entity, we can determine the value of one other entity

Question 39

Given the functional dependency A -> (B, C), A is a

Answer 39

Determinant

Question 40

Given the functional dependency (A, B) -> C, (A, B) is a

Answer 40

Determinant and composite determinant

Question 41

Given the functional dependency (A, B) -> C, then

Answer 41

None of the above

Question 42

Which of the following is true about the functional dependency A -> (X, Y)?

Answer 42

X is functionally dependent on A, A determines Y, A is a determinant, X and Y are functionally dependent on A

Question 43

Which of the following is true about the functional dependency (A, B) -> (C, D)?

Answer 43

A and B together determine D

Question 44

The only reason for having relations is to

Answer 44

Store instances of functional dependencies

Question 45

A combination of one or more columns used to identify particular rows in a relation is a

Answer 45

Key

Question 46

A combination of two or more columns used to identify particular rows in a relation is a

Answer 46

Composite key

Question 47

A determinant determines all the other columns in a relation is a

Answer 47

Candidate key

Question 48

When designing a database, one of the candidate keys in a relation is selected as the

Answer 48

Primary key

Question 49

An artificial columnar added to a relation to serve as the primary keys is a

Answer 49

Surrogate key

Question 50

A key consisting of one or more columns is that a primary key in another relation is a

Answer 50

Foreign key

Question 51

A referential integrity constraint is used to make sure the values of a foreign key match a valid value of a primary key.

Answer 51

True

Question 52

A constraint that requires an instance of an entity to exist in one relation before it can be referenced in another relation is called an insertion anomaly

Answer 52

False

Question 53

A referential integrity constraint limits the values of a foreign key.

Answer 53

True

Question 54

If a table meets the minimum definition of a relation, it has an effective or appropriate structure.

Answer 54

False

Question 55

Undesirable consequences of changing the data in a relation are called "modification anomalies"

Answer 55

True

Question 56

A deletion anomaly exists when deleting data about one entity results in the loss of data about another entity

Answer 56

True

Question 57

Relations are classified into "normal forms" based on the types of modification anomalies that they are vulnerable to.

Answer 57

True

Question 58

Any table that meets the definition of a relation is said to be in first normal form (1NF).

Answer 58

True

Question 59

Any table that meets the definition of a relation is in 2NF.

Answer 59

False

Question 60

A relation is in 2NF if and only if it is in 1NF and all non-key attributes are determined by the entire primary key.

Answer 60

True

Question 61

A relation is in 3NF if and only if it is in 2NF and there are no non-key attributes determined by another non-key attribute.

Answer 61

True

Question 62

Referential integrity constraints are used to limit the possible values of a

Answer 62

Foreign key

Question 63

A ______ is used to limit the possible values of a(n) foreign key

Answer 63

Referential integrity constraint

Question 64

Normalization is a process used to deal with which of the following modification anomalies?

Answer 64

Insertion anomaly, update anomaly, deletion anomaly

Question 65

If the removal of facts about one entity results in the unintentional loss of data about another entity, this is referred to as an

Answer 65

Deletion anomaly

Question 66

Suppose that you need to update one value if the column SalesCost in a relation. The way the relation is constructed, this value actually needs to be changed in three different rows. However, you can only change the value in two of the rows. You have just created a(n)

Answer 66

Update anomaly

Question 67

A table that meets the definition of a relation is in

Answer 67

First normal form

Question 68

A relation is in second normal form (2NF) if and only if it is in 1NF and

Answer 68

All non-key attributes are determined by the entire primary key

Question 69

A relation is in Boyce-Codd normal form (BCNF) if and only if it is in 3NF and

Answer 69

Every determinant is a candidate key

Question 70

If a table is designed so that every determinant is a candidate key, then that relation is in ____

Answer 70

Boyce-Codd Normal Form

Question 71

The condition that a non-key attribute determines another non-key attribute is known as transitive dependency

Answer 71

True

Question 72

An attribute is considered to be a non-key attribute when it is a non-prime attribute, which means that the attribute is not contained in any candidate key

Answer 72

True

Question 73

Candidate keys are called interlocking candidate keys when they share one or more attributes

Answer 73

False

Question 74

A relation is in Boyce-Codd Normal Form (BCNF) if and only if it is in 3NF and every determinant is a candidate key

Answer 74

True

Question 75

A defining requirement for a Boyce-Codd Normal Form (BCNF) is that every candidate key must be a determinant

Answer 75

False

Question 76

Every time we break up a relationship during the normalization process, we may have to create a referential integrity constraint

Answer 76

True

Question 77

The essence if normalization is taking a relation that is not in BCNF and breaking it into multiple relations such that each one is in BCNF

Answer 77

True

Question 78

When designing or normalizing relations, each relation should have only one theme

Answer 78

True

Question 79

A multivaried dependency exists when a determinant is matched to a set of values

Answer 79

True

Question 80

The multivalued dependency noted A -> -> B, means that the value of A determines a set of values of B

Answer 80

True

Question 81

A relation is in 4NF when multivalued dependencies are isolated in their own relation

Answer 81

True

Question 82

A relation is in 4NF if it is in BCNF and it has no multivalued dependencies

Answer 82

True

Question 83

Domain/key normal form requires that every constraint be logical consequence of the definition of domains and keys

Answer 83

True

Question 84

A relation that is in domain/key normal form is assured to be free from all anomalies

Answer 84

True

Question 85

If a relation is in BCNF and each multivalued dependency has been moved to a relation of its own, then the first relation is in _____

Answer 85

Fourth Normal Form

Question 86

A relation is in forth normal form if it is in BCNF and it has no____

Answer 86

Multivalued dependencies

Question 87

A relation is in domain/key normal form if _____

Answer 87

Every constraint on the relation is a logical consequence of the definition of keys and domains

Question 88

In general, each relation should have ______

Answer 88

One and only one theme