Section 2

Question 1

Have you ever had trouble finding a document in a filing cabinet or folder that someone else organized?
The files may have been organized to meet that person’s needs, but not your own.

Answer 1

Data modeling attempts to capture the needs of the business users so that the resulting database is one that everyone can use.

Question 2

When you are able to recognize and analyze information, you can better ………… how things work and potentially make them ……….

Answer 2

understand / better

For example:
−How to make the line at the food counter go faster
−How to successfully exchange an item at the store
−How to organize and keep track of your growing CD collection

Question 3

Also, recognizing and analyzing information helps prevent …………. and ………….

Answer 3

mistakes / misunderstanding

For a business, this is important because it saves time and money

Question 4

A conceptual model Is the result of completing the ………. ………. ……….

Answer 4

Data Modeling process

Question 5

A conceptual model Addresses the needs of a business (what is …………. ………….), but does not address its implementation (what is ………… …………)

Answer 5

conceptually ideal / physically possible

Question 6

A conceptual model:

1. Is based on current needs but it may reflect future needs
2. Captures the …………. and ……….. ………… of a business

Answer 6

1. FYI
2. functional / informational needs

Question 7

A conceptual model: −Identifies :

1. important ………… (objects that become ……… in database)
2. ………… among …………

Answer 7

1. entities / tables
2. relationships / entities

Question 8

A conceptual model: −Does not specify :

1. ………….. (objects that become ………… or ………. in database)
2. ………… …………. (attribute that becomes ………. ………. in database)

Answer 8

1. attributes / columns / fields
2. unique identifiers / primary key

Question 9

A conceptual model is important to a business because it:

1. Describes exactly the ………. ……….. of the business
2. Facilitates …………..

Answer 9

1. information needs
2. discussion

Question 10

A conceptual model is important to a business because it:

1. Prevents ………… and …………..
2. Forms important “ideal system” …………..

Answer 10

1. mistakes / misunderstandings
2. documentation

Question 11

A conceptual model is important to a business because it:

1. Forms a sound basis for ……… …….. ……….
2. Documents the ………. (also known as the “business rules”) of the business

Answer 11

1. physical database design
2. processes

Question 12

A conceptual model is important to a business because it:

Takes into account ……………… and …………. governing this industry

Answer 12

regulations and laws

Question 13

A logical model is called an ……….. ……….. ………. and is illustrated in an …………

Answer 13

entity relationship model (ERM) / ERD

Question 14

A logical model Includes all entities and relationships among them

Answer 14

R 2

Question 15

A logical model

1. Specifies all ………… and …….. for each entity
2. Determines …………. …………
3. Determines relationship ……….. and ………….

Answer 15

1. attributes / UIDs
2. attribute optionality
3. optionality / cardinality

cardinality: the number of elements (= separate items) in a mathematical set

Question 16

A physical model:

Is an extension to a logical data model

• Defines (3)
• Identifies ……….., …………., and other database objects

Answer 16

1. table definitions, data types, and precision
2. views, indexes

Question 17

A physical model

1. Describes how the objects should be implemented in ………. ………..
2. Shows all ………… structures, including (3)

Answer 17

1. specific database
2. table / columns, primary keys, and foreign keys

Question 18

Answer 18

Question 19

Entities can be: (3)

Answer 19

1. Tangible, like PERSON or PRODUCT
2. Intangible, like SKILL LEVEL
3. An event, like CONCERT

Question 20

It would not make sense to have an entity with only one ………………

Answer 20

instance

Question 21

Both the entity and the attribute represents something of ………….. to the business

Answer 21

significance

Question 22

An attribute is a specific piece of information that
helps:

…………. an entity

………….. an entity

………… an entity

………….. an entity

…………. an entity

Answer 22

1. Describe
2. Quantify
3. Qualify
4. Classify
5. Specify

Question 23

An attribute has a ……….. ………..

Answer 23

single value

Question 24

Attributes have values. An attribute value can be a number, a character string, a date, an image, a sound, etc. These are called “…………” or “…………..”

Answer 24

data types / formats

Question 25

Data type: A classification: 1. identifying one of various types of data, 2. stating the possible values for that type, 3. the …………… that can be done on that type, and 4. the way the values of that type are ………….

Answer 25

1. FYI 2. FYI 3. operations 4. stored *Single-valued: Can only have one value at any point for each instance in the entity*

Question 26

An attribute for an entity must be single-valued. In more precise terms, an instance of an entity can have only one value for each attribute at any point in time. This is the most important characteristic of an attribute. The attribute value, however, may change over time.

Answer 26

For example: The entity CAR may have attributes “model” and “color.” There can be only one value for these (for example, “Beetle” and “green”) at one time, for each instance (i.e. for each individual car). Although the model remains the same over the lifetime of the car, its color can change.

Question 27

Some attributes (such as age) have values that constantly change These are called …………. attributes

Answer 27

volatile

Question 28

Other attributes (such as order date) will rarely change, if ever, these are ………….. attributes

Answer 28

nonvolatile

Question 29

If given a choice, select the ………….. attribute

Answer 29

nonvolatile *For example, use birth date instead of age*

Question 30

A good conceptual data model stays the same regardless of the type of database the system is eventually built—or implemented—on. This is what we mean when we say that the model is “……………………”

Answer 30

implementation-free

Question 31

There are four goals of ER modeling: 1. Capture all ……….. ……….. 2. Ensure that data appears ……… ………. 3. Model no data that is ……….. from other data already modeled 4. Locate data in a …………, ………. ………..

Answer 31

1. required data 2. only once 3. derivable 4. predictable / logical place