Deck 3: The Relational Model and Normalization

Question 1

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

Answer 1

True

Question 2

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

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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 5

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

Question 6

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

Question 7

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

Question 8

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

Question 9

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

Question 10

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

Question 11

The columns of a relation are sometimes called tuples.

Question 12

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

Question 13

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

Question 14

A relation is a table composed of columns and rows.

Question 15

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

Question 16

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

Question 17

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

Question 18

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.

Question 19

Functional dependencies can involve groups of attributes.

Question 20

A relation is a table that has special restrictions on it.

Question 21

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

Question 22

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

Question 23

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

Question 24

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

Question 25

Surrogate keys usually slow performance.

Question 26

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

Question 27

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

Question 28

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

Question 29

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

Question 30

Surrogate keys are normally not shown on forms or reports.

Question 31

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

Question 32

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

Question 33

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 34

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

Question 35

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

Question 36

A row can be uniquely identified by a key.

Question 37

A relation can have only one candidate key.

Question 38

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

Question 39

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

Question 40

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

Question 41

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

Question 42

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

Question 43

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

Question 44

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

Question 45

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

Question 46

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 47

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

Question 48

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 49

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

Question 50

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

Question 51

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 52

Which of the following is not true about 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)Can have two identical rows

Question 53

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

Question 54

Which of the following is true for 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.

Question 55

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

Question 56

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 57

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

Question 58

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

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

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

Question 61

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

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

Question 62

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

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

Question 63

An attribute is also known as a ________.

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

Question 64

Which of the following is NOT true about the functional dependency A → (X,Y)?

A)X is functionally dependent on A.
B)A determines Y.
C)X and Y together determine A.
D)X and Y are functionally dependent on A.

Question 65

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.

Question 66

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

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

Question 67

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

Question 68

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

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

Question 69

Having to enter facts about two entities when we want to enter facts about only one is an example of ________.

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

Question 70

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

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

Question 71

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

A)dependent variable
B)determinant
C)composite determinant
D)Both B and C are correct

Question 72

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

Question 73

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

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

Question 74

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

Question 75

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

Question 76

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

Question 77

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

A)A and B together → C
B)A → C
C)B → A
D)Both A and B are correct

Question 78

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

Question 79

A tuple is also known as a ________.

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

Question 80

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

A)store instances of functional dependencies
B)store equation components
C)store equation results
D)Both B and C are correct