Deck 3: The Relational Model and Normalization

Question 1

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

Answer 1

True

Question 2

In the functional dependency shown as A → B,B is the determinant.

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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

Question 5

Functional dependencies can involve groups of attributes.

Question 6

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.

Question 7

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

Question 8

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

Question 9

The columns of a relation are sometimes called tuples.

Question 10

A relation is a table composed of columns and rows.

Question 11

The functional dependency noted as A → B means that the value of A can be determined from the value of B.

Question 12

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

Question 13

A relation is a three-dimensional table.

Question 14

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

Question 15

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

Question 16

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

Question 17

Given the functional dependency A → B,then it is necessarily true that B → A.

Question 18

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

Question 19

All relations are tables,but not all tables are relations.

Question 20

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

Question 21

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

Question 22

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

Question 23

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

Question 24

Surrogate keys usually slow performance.

Question 25

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

Question 26

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

Question 27

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

Question 28

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

Question 29

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

Question 30

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

Question 31

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

Question 32

A row can be uniquely identified by a key.

Question 33

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

Question 34

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

Question 35

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

Question 36

A relation can have only one candidate key.

Question 37

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

Question 38

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.

Question 39

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

Question 40

Surrogate keys are normally not shown on forms or reports.

Question 41

A relation ________.

A)has rows containing data about an entity
B)has columns containing data about attributes of the entity
C)has cells that hold only a single value
D)has no two identical rows
E)All of the above.

Question 42

In a relation ________.

A)entities in a column vary as to kind
B)the order of the columns is important
C)the order of the rows is unimportant
D)more than one column can use the same name
E)All of the above.

Question 43

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

Question 44

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

Question 45

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

Question 46

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

Question 47

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

Question 48

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

Question 49

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

Question 50

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

Question 51

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

Question 52

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

Question 53

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

Question 54

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

Question 55

The multivalued dependency noted as A → → B,means that the value of A determines a set of values of B.

Question 56

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.

Question 57

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

Question 58

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

Question 59

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.

Question 60

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.

Question 61

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

A)record
B)field
C)key
D)tuple
E)dependency

Question 62

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

A)X is functionally dependent on A.
B)A determines Y.
C)A is a determinant.
D)X and Y are functionally dependent on A.
E)All of the above.

Question 63

An artificial column added to a relation to serve as the primary key is a ________.

A)composite key
B)candidate key
C)foreign key
D)surrogate key
E)dependency

Question 64

Given the functional dependency (A,B)→ C,(A,B)is a(n)________.

A)independent variable
B)dependent variable
C)determinant
D)composite determinant
E)C and D

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 a(n)________.

A)normalization anomaly
B)insertion anomaly
C)update anomaly
D)deletion anomaly
E)removal anomaly

Question 66

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

A)composite key
B)candidate key
C)foreign key
D)surrogate key
E)dependency

Question 67

Saying that two entities are functionally dependent means that ________.

A)the entities are always connected by a mathematical equation
B)for one of the entities,if we are given the value of that entity,we can determine the value of one other entity
C)for both of the entities,if we are given the value of one entity,we can determine the value of the other entity
D)the functional dependency will have to be removed through normalization
E)All of the above.

Question 68

The only reason(s)for having relations is to ________.

A)store instances of functional dependencies
B)store equation components
C)store equation results
D)B and C
E)A,B,and C

Question 69

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

A)composite key
B)surrogate key
C)functional dependency
D)referential integrity constraint
E)normal form

Question 70

A determinant that determines all the other columns in a relation is a ________.

A)record
B)field
C)foreign key
D)candidate key
E)surrogate key

Question 71

A relation is also known as a(n)________.

A)table
B)tuple
C)relationship
D)attribute
E)field

Question 72

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

A)composite key
B)primary key
C)foreign key
D)surrogate key
E)dependency

Question 73

An attribute is also known as a(n)________.

A)table
B)relation
C)row
D)field
E)file

Question 74

A tuple is also known as a(n)________.

A)table
B)relation
C)row
D)field
E)file

Question 75

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

A)record
B)field
C)composite key
D)foreign key
E)surrogate key

Question 76

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

A)composite key
B)candidate key
C)foreign key
D)surrogate key
E)dependency

Question 77

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

A)A is the determinant of C.
B)A and B together are determined by C and D together.
C)A and B together determine D.
D)C and D together determine A.
E)A determines B.

Question 78

Given the functional dependency A → (B,C),A is a(n)________.

A)independent variable
B)dependent variable
C)determinant
D)composite determinant
E)C and D

Question 79

Given the functional dependency (A,B)→ C,then ________.

A)A → B
B)A → C
C)B → A
D)B → C
E)None of the above is correct.

Question 80

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

A)Insertion anomaly
B)Update anomaly
C)Deletion anomaly
D)A and B
E)A,B,and C