chapter 4 review

Question 1

t or f: the relational DB model offers a logical view of data?

Answer 1

true

Question 2

view data logically rather than physically?

Answer 2

relational model

Question 3

structural and data independence.
resembles a file conceptually?

Answer 3

table

Question 4

t or f: relational DB model is harder to understand than the hierarchical and network model?

Answer 4

false

Question 5

logical view of relational DB is based on….

Answer 5

relation

Question 6

two-dimensional structure composed of rows and columns.

Answer 6

table

Question 7

t or f: a table contains a group of related entities?

Answer 7

true

Question 8

one or more attributes that determine other attributes

Answer 8

key

Question 9

t or f: key roles means if you know the value of attribute A, you can determine the value of attribute B

Answer 9

t

Question 10

attribute B is functionally dependent on A if all rows in the table that agree in value for A also agree in the value of B, this is def of?

Answer 10

functional dependence

Question 11

composed of more than one attribute?

Answer 11

composite key

Question 12

any attribute that is a part of a key

Answer 12

key attribute

Question 13

any key that uniquely identifies each row

Answer 13

superkey

Question 14

a superkey without unnecessary attributes

Answer 14

candidate key

Question 15

each row in a table has its unique identity

Answer 15

entity integrity

Question 16

no data entry is an example of?

Answer 16

nulls

Question 17

makes the relational DB work?

Answer 17

controlled redundency

Question 18

t or f: data within the same DB share the same attributes

Answer 18

true

Question 19

t or f: redundancy exists only when there is unnecessary duplication of attribute values?

Answer 19

true

Question 20

an attribute whose values match primary key values in a related table

Answer 20

foreign key

Question 21

FK contains a value that refers to an existing valid tuple in another relation

Answer 21

referential integrity

Question 22

key used strictly for data retrieval purposes

Answer 22

secondary key

Question 23

t or f: many relational database managements enforce integrity rules automatically

Answer 23

true

Question 24

flags indicate the absence of some values

Answer 24

using flags to avoid nulls

Question 25

provides a detailed accounting of all tables found within a user-created database

Answer 25

data dictionary

Question 26

t or f: data dictionary contains all attribute names and characteristics for each table in the system and metadata

Answer 26

true

Question 27

detailed system data dictionary that describes all objects within the database

Answer 27

system catalog

Question 28

indicates the use of the same name to label different attributes

Answer 28

homonym

Question 29

indicates the use of different names to label the same attribute

Answer 29

synonym

Question 30

relational modeling ideal

Answer 30

1:m

Question 31

should be rare in any relational DB design

Answer 31

1:1

Question 32

cant be implemented can be changed into 1:m relationships

Answer 32

m:n

Question 33

what relation is found in any DB environment?

Answer 33

1:m

Question 34

sometimes means that entities were not defined properly

Answer 34

1:1

Question 35

avoid problems inherent to m:n relationship by creating a composite key in which relation?

Answer 35

m:n

Question 36

controls data redundancy by using common attributes shared by table in the?

Answer 36

FK

Question 37

t or f: data redundancy is not necessary

Answer 37

false