Z556: Session 8
Data Modeling
 Entity-Relationship Diagram (ER).
 Unified Modeling Language (UML).
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Modeling
Cultural Model
Flow Model
Physical Model
Artifact Model
Sequence Model
E-R Diagram
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What is Data Modeling?
A process for
identifying, documenting & organizing
data elements based on specified
requirements.
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What is Data Modeling?
A design activity that is not
limited to data analysis.
(Be Creative…)
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What is Data Modeling?
Can be presented in many different
ways.
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E.g.,
Tables
Entity-Relationship
diagram
Class diagram
Activity diagram
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Why Data Modeling?
To identify essential data elements and
understand their role in supporting
business processes.
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A Little Incentive to Pay Attention
Annual Mean Salary by Job
Financial specialist
Information and Record Clerks
Loan officer
Network & Computer Systems
administrator
Paralegals
Database administrator
$74,270
$32,320
$71,800
$77,910
$51,170
Advertising Sales Agents
$80,740
$57,440
Actuaries
$107,740
Bureau of Labor Statistics http://www.bls.gov/oes/current/oes_nat.htm
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Data Modeling Language
Entity-Relationship (ER) Diagram
Object-Oriented (OO) Design
Unified Modeling Language (UML)
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Case Study: KCCI Training Center
• KCCI training center organizes training programs
for customers in three different areas: Investment,
Real-Estate, & Human-Resources.
• For each program to run, there is a required
minimum number of attendees.
• To enroll in a program or more, a customer fills a
registration form and send it to the center.
• A training coordinator keeps track of the number
of registered customers. When the minimum
number is reached before the start date of the
program, the coordinator contacts a trainer to run
the program and then sends confirmation/invoice
letters to the customers.
• If no trainer is available or the minimum number
is not reached, cancelation letters are sent to the
customers.
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Case Study: KCCI Training Center
Problems:
 Ineffective paper-based system that fails to
meet the growing trends of the center.
 Difficulty to track programs and participants.
 Difficulty to locate misplaced or lost files.
 Difficulty to share and access information.
 Underutilized data for future planning.
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Case Study: KCCI Training Center
Solution:
Develop a new information system for
managing, storing, retrieving, and
analyzing all information related to
training programs.
Purpose of data modeling:
To identify essential data elements and
understand their role in supporting
work processes.
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ER Diagram
Entity
Relationship
Attribute
o The principle data objects about which
information is to be collected.
E.g., person, place, document, etc.
o Entity instance: a particular occurrence of an
entity.
Instances
University
•Indiana University Bloomington
•University of Indianapolis
•University of Phoenix
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ER Diagram
Entity
Relationship
Attribute
Real-word association among entities.
Entity
Relationship
Entity
Manager
Manages
Department
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ER Diagram
Entity
Relationship
Attribute
o Connectivity of a relationship :
Describes the constraints on the connection of
the associated instance in the relationship.
Entity
1
Entity
1
Entity
*
1
Entity
Relationship
*
Entity
Relationship
*
Entity
Relationship
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ER Diagram
Entity
Relationship
Attribute
o Provides descriptive detail about entities and
relationships.
o An attribute value: a particular occurrence of
an attribute within an entity or relationship.
ID
name
Section
date
Student
enroll
Class
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Title
KCCI ER Diagram
CoID
iscontactedby
1
Coordinator
Name
1
contacts
1
Address
Manage
s
Date
*
Customer
*
enrolls
*
*
Program
is
given
by
*
*
Trainer
1
ProgID
Name
CustID
Phone
Name
Area
Title
TrnID
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KCCI ER Diagram
CoID
iscontactedby
1
Coordinator
Name
1
contacts
1
Manage
Address
Date
*
Customer
*
enrolls
*
*
Program
is
given
by
*
*
Trainer
1
ProgID
Name
CustID
Phone
Name
Area
Title
TrnID
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KCCI ER Diagram
CoID
iscontactedby
1
Coordinator
Name
1
contacts
1
Manage
Address
Date
*
Customer
1
* Registration *
1
Form
*
Program
is
given
by
*
*
Trainer
1
ProgID
Name
CustID
Phone
Name
Area
Title
TrnID
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Implementing
Cust#
100
Name
Peter Alex
Address
335 10th
Phone #
555-4444
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Entity (Customer)
Implementing
Attribute
(address)
Cust#
100
Name
Peter Alex
Address
335 10th
Phone #
555-4444
data instance
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Entity
Many-to-Many Relationship
Cust_id F_name
L_name
address
Registration
1234
Mary
Gray
456 Oak street
1235
Bill
Dodds
789 Woodburn street
1236
Justin
Moore
903 College avenue
Class_i
d
Price
Date
Class name
135
100
Oct-1-2013
Customer Service 101
136
200
Nov-1-2013
Types of Investment
137
100
Oct-31-2013 Property Evaluation
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Many-to-Many Relationship
CUSTOMER
Cust_id
F_name
L_name
Address
REGISTRATION
Registration_id
0088
Cust_id
1234
Class_id
136
PRODUCT
Class_id
Price
Date
Class name
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Generalization Hierarchy Diagram
Entities with common attributes can be
generalized into a higher entity type
(Superset entity).
Subsets entities can be either
disjoint (d) or overlapping (o).
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Hierarchy Diagram
Overlap (o) Generalization
Name
Disjoint (d) Generalization
StartDate
Phone
ProgID
PerID
EndDate
Email
Program
Person
d
o
Customer
Coordinator
Trainer
Real-Estate
Investment
HumanResources
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Object-Oriented (OO) Design
Objects are the basic unit which the organization must
keep track of or that participate in a business process.
A system is a set of objects that collaborate and interact
with each other.
UML is a widely accepted standard incorporating OO
concepts, and provides terminology and diagram
conventions.
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Object-Oriented Design
Attributes:
• Properties attached to each object.
Operations :
• Functions that could change the value of
object’s attribute.
Methods:
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• Procedure used to carry on the operations.
OO Concepts
• Classes:
Categories to which an object belong to and share the same
operation, methods, and attributes.
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Class Name
Customer
Attribute 1
Attribute 2
Attribute 3
Operation 1 ()
Operation 2 ()
Operation 3 ()
CustomerID
Name
Address
SearchProgram()
Enroll ()
Pay ()
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Class Relationships in UML
Generalization:
A relationship between a more general class and
a more specific class.
Program
Real-Estate
Investment
HumanResources
Association:
Objects in one class linked to objects in the other
class.
Multiplicities: 1 to 1 , 1 to * , * to *
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Coordinator
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Program
Class Relationships in UML
Aggregation:
Relationship between a whole and its parts.
Trainer
Program
Composition:
An aggregation relation in which the part belong to only one
whole at a time.
ProgramDescripton
Purpose
TargetAudience
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Program
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UML Class Diagram
(Attributes)
1..1
1..*
1..*
Trainer
Program
<pk>TrainerID
Name
PlaceOfWork
Phone
Fax
Email
Note
<pk>ProgramID
Title
TrainingArea
Location
StartDate
EndDate
StartTime
EndTime
Cost
MinAttendees
Coordinator
Status
Note
1..*
1..1
1..1
RegistrationForm
<pk>RegFormID
Date
<pk>CustomerID
<pk>ProgramID
Note
1..1
<pk>CoordinatorID
Name
Phone
Email
Note
<pk>CustomerID
Title
Name
Phone
Fax
Email
Work
Note
1..1
1..*
1..1
Coordinator
Customer
Association Class
Invoice
<pk>InvoiceID
Date
RegistrationForm
Cost
Note
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UML Class Diagram
(Operation)
Trainer
AddTrainer()
RemoveTrainer()
isAvailable(:Boolean)
1..1
1..*
Program
1..*
1..*
AddProg ()
ConfirmProg ()
CancelProg()
1..*
1..1
Coordinator
ProgStatus ()
ConfirmLetter ()
CanelLetter ()
ContactTrainer()
1..1
1..1
RegistrationForm
AddProgram()
RemoveProgram()
AddCustomer()
RemoveCustomer()
Customer
NewCust()
SignIn()
FindProgram()
Enroll(in enrl: Program)
SendRegForm()
Payment()
1..1
1..1
Invoice
Total (amnt: Dollar)
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Summary
Data modeling help identify essential data elements and
understand their role in supporting business processes.
Data modeling simplifies communication between system
developers and end users.
Data modeling supports the development of information
systems.
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Develop a Data Model
for Choosing a Job?
• What are the entities/classes?
• What are the attributes?
• What are the relationships?
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Develop a Data Model
for Choosing a Job?
1..1
1..*
ContactPerson
Job
<pk>CP_ID
Name
Phone
Fax
Email
Note
<pk>JobID
<pk>CP_ID
<pk>OrgID
Title
Salary
Responsibilities
Requirements
StartDate
Location
Note
1..*
1..1
Organization
<pk>OrgID
Name
Phone
Fax
Email
Website
Type
Note
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The 7 Habits of Highly Effective Data Modelers
(Moody, 1996)
Knowledge
Skill
Motivation
Habit
Moody, D. (1996) The seven habits of highly effective data modelers.
Database Programming & Design, 9, 10, 57-64.
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The 7 Habits of Highly Effective Data Modelers
(Moody, 1996)
• See for yourself (observation—Method school of data
modeling)
• Generate alternatives
• Keep it simple (generalization)
• Test the model (prototyping/scenario)
• Know when to stop
• Remember the big picture
• Following through
• Contextual Inquiry
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Object-Orientation
Attributes:
Color; Size
ILS Z556
• Objects
• An object has attributes and operations
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Object-Orientation
• Objects
Operations:
Make a call
ILS Z556
• An object has attributes and operations
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Object-Orientation
• A class is a category to which an object belongs
ILS Z556
• E.g., Smartphone is a class for Nexus and iPhone; both
share the same attributes and operations
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Object-Orientation
• Attributes of: size,
location, background
color, etc.
ILS Z556
• Window is a class
that has:
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Object-Orientation
• Operations of: open,
close, resize, etc.
ILS Z556
• Window is a class
that has:
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UML and ER
• UML class diagrams =~ ER diagrams
• Classes =~ Entities
Attribute 1
Class Name
Attribute 1
Attribute 2
Operation 1()
Operation 2()
Entity Name
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UML and ER
• UML class diagrams =~ ER diagrams
• Classes =~ Entities
Example
Class Name
Customer
Attribute 1
Attribute 2
<pk>Customer_id: string
Customer_name: string
Address: string
Operation 1()
Operation 2()
creditRating ()
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UML and ER
• UML class diagrams =~ ER diagrams
• Classes =~ Entities
Example
Create
Read
Update
Delete
Class Name
Customer
Attribute 1
Attribute 2
<pk>Customer_id: string
Customer_name: string
Address: string
Operation 1()
Operation 2()
creditRating ()
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UML: Class Diagram
Customer
Order
name
address
0..*
1
association
Payment
date
status
calcTax
calcTotal
calcTotalWeight
1
1
1..*
aggregation
amount
line item
1..*
OrderDetail
specialization
quantity
taxStatus
Credit
number
type
expDate
Cash
cashTendered
Check
name
bankID
calcSubTotal
calcWeight
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authorized
authorized
http://edn.embarcadero.com/article/images/31863/classdiagramno3d.gif