chapter 8-14

Question 1

data modeling

Answer 1

a technique for organizing and documenting a systems data.

sometimes called database modeling

Question 2

entity relationship diagram

Answer 2

a data model utilizing several notations to depict data in terms of the entities and relationships described by that data

Question 3

entity

Answer 3

person, place, thing, etc that the business needs to capture and store data

Question 4

attribute

Answer 4

a descriptive property or characteristic of an entity

Question 5

compound attribute

Answer 5

an attribute that consists of other attributes

Question 6

attribute value

Answer 6

the value of each attribute should be defined in:

data type, domain, default value

Question 7

key

Answer 7

an attribute, or group of attributes, that assumes a unique value for each entity instance

Question 8

concatenated key

Answer 8

group of attributes that uniquely identifies an instance

Question 9

candidate key

Answer 9

an attribute that uniquely identifies an instance

Question 10

primary key

Answer 10

a candidate key used to uniquely identify a single entity instance

Question 11

cardinality

Answer 11

the minimum and maximum number of occurrences of one entity that may be related to a single occurrence of the other entity

Question 12

degree

Answer 12

the number of entities that participate in the relationship

Question 13

unary relationship

Answer 13

a relationship between different instances of the same entity

Question 14

binary relationship

Answer 14

a relationship between two entities

Question 15

ternary relationship

Answer 15

a relationship between three entities

Question 16

associative entity

Answer 16

an entity that inherits its primary key from more than one other entity

Question 17

foreign key

Answer 17

primary key of an entity that is used in another entity to identify instances of a relationship

Question 18

what is a good data model?

Answer 18

a good data model is…

simple, non redundant, flexible and adaptable to future needs

Question 19

data analysis

Answer 19

a technique used to improve a data model for implementation as a database

Question 20

normalization

Answer 20

a data analysis technique that organizes data attributes such that they are grouped to form non redundant, stable, and adaptive entities

Question 21

1NF

Answer 21

entity whose attributes have only one value for a single instance of that entity

Question 22

2NF

Answer 22

entity whose non primary key attributes are dependent on the full primary key

no partial dependencies on a composite primary key

Question 23

partial dependency

Answer 23

when a non key attribute is determined by a part but not the whole of a composite primary key

Question 24

3NF

Answer 24

entity whose non primary key attributes are not dependent on any other non primary key attributes

no transitive dependency

Question 25

transitive dependency

Answer 25

when a non key attribute determines another non key attribute

Question 26

method for database design

Answer 26

1. review the logical data model
2. create a table for each entity
3. create fields for each attribute
4. designate foreign keys for relationships
5. define data types, sizes, null settings, domains, and default value for each attribute
6. evaluate database integrity

Question 27

key integrity

Answer 27

every table should have a primary key

Question 28

domain integrity

Answer 28

appropriate controls must be designed to ensure that no field takes on an inappropriate value

ex) valid date

Question 29

referential integrity

Answer 29

ensures that a foreign key value in one table has a matching primary key value in the related table