SYST 430: BIS Analysis & Development
Business Information Systems
Analysis
Spring 2003
Abou-Bakr Zayd
aboubakr@K4B.net
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
1
BIS & e-commerce Quality Life-Cycle
Quality Life-Cycle
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
2
Data Flow Diagrams (DFD):
ANALYSIS: Data & Process Modeling
• DFD shows how data moves through an IS (what the system
does) but doesn’t show program logic or processing steps (how
it does it)
• That distinction is important because focusing on
implementation issues at this point would restrict the search for
the most effective system design
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
3
Data Flow Diagrams (DFD): Symbols
ANALYSIS: Data & Process Modeling
Gane & Sarson Symbols
Symbol Name
Process
Apply
Students
Customer
Copyright © 2003 Abou-Bakr Zayd
Apply
Payment
Payment
Bank Deposit
Yourdon Symbols
Data Flow
Bank Deposit
Data Store
Students
External Entity
Customer
BIS Analysis
4
Data Flow Diagrams (DFD): Process Symbol
ANALYSIS: Requirements Modeling
• A Process receives I/P data & produces O/P data that has a
different content
• Processes are black boxes that contain the business logic/rules
that transforms the data & produce required results
Hours Worked
Calculate
Pay Rate
Gross Pay
Gross
Pay
Hours Worked
Calculate
Gross
Pay Rate
Black Hole
Pay
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
5
Data Flow Diagrams (DFD): Data Flow Symbol
ANALYSIS: Requirements Modeling
• A Data Flow is a path for data to move from one part of the IS
to another
• A Data Flow in a DFD represent one or more data items; the
diagram doesn’t show its structure & detailed contents
Graded Work
Submitted Work
Date of Birth
Copyright © 2003 Abou-Bakr Zayd
Grade
Student
Work
Grade
Student
Work
Student Grade
Final Grade
Gray Hole
BIS Analysis
6
Data Flow Diagrams (DFD): Data Store Symbol
ANALYSIS: Requirements Modeling
• A Data Store is used to retain data because processes need to
use the stored data at a later time
• DFD doesn’t show the detailed contents of a data store; the
specific structure & data elements are defined in data dictionary
Create
Invoice
Courses
Invoice
Accounts Receivable
Invoice
Detail
Payment
Detail
Class
List
Students
Post
Payment
Customer
Payment
Payments
Book
Flight
Flight
Request
Passengers
Post
Payment
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
7
Data Flow Diagrams (DFD): External Entity Symbol
ANALYSIS: Requirements Modeling
• An External Entity is a person, department, outside
organization, or other IS that provides data or receives O/P
• External Entities show the boundaries of the IS and how it
interacts with the outside world
Customer
Order
Invoice
Verify
Order
Copyright © 2003 Abou-Bakr Zayd
Payroll
Department
Customer
Paycheck
Payment
Employee
Accounts
Bank
Bank
Deposit
Payments
BIS Analysis
8
Data Flow Diagrams (DFD): Context Diagrams
ANALYSIS: Data & Process Modeling
• Based on fact-finding results gathered during requirements
modeling (through different fact finding techniques), information
about how various people, departments, data, and processes fit
together to support business operations can now be
represented graphically
• Context Diagram: is a top level view of an IS that shows
system boundaries & scope
• To draw a context diagram, a single process symbol (process 0)
that represents the entire IS is placed in the center of the page
and all external entities are placed around the perimeter of the
page then data flows are used to connect the entities to the
central process
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
9
Data Flow Diagrams (DFD): Context Diagram
ANALYSIS: Requirements Modeling
Students
Records
System
Final
Grade
Submitted
Work
Student
Class
Roster
0
Graded
Work
Grading
System
Grading
Parameters
Grade
Report
Instructor
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
10
Data Flow Diagrams (DFD): Diagram 0
ANALYSIS: Requirements Modeling
Students
Records
System
Final
Grade
2
Assign
Final
Grade
Student
Grading Detail
Submitted
Work
Class
Roster
Grade Book
Grade Book
Student Grade
1
3
Establish
Grade
Class Detail
Grade
Student
4
Book
Work
Produce
Grade
Grading
Report
Parameters
Graded
Work
Grade
Report
Instructor
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
11
Data Flow Diagrams (DFD): Strategies & Rules
ANALYSIS: Data & Process Modeling
• There are different strategies for developing a set of DFDs:
– Top-Down
– Bottom-Up
• Conventions for DFDs:
–
–
–
–
–
Each context diagram must fit in one page
The process name in the context diagram should be the name of the IS
Use unique names within each set of symbols
Do not cross lines
Use a unique reference number for each process symbol
• Balancing: preserving the I/P & O/P data flows of the parent on
the child DFD
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
12
Data Dictionary: Overview
ANALYSIS: Data & Process Modeling
• A set of DFDs produces a logical model of the system but the
details within those DFDs are documented separately in a Data
Dictionary
• A Data Dictionary or Data Repository is a central storehouse
of information about the system’s data, where analysts collect,
document & organize specific facts about the system including
the contents of data flows, data stores, external entities &
processes
• Data Dictionary defines & describes all data elements &
meaningful combinations of data elements
• Data Element (item or field) is the smallest piece of data that
has meaning within an IS (e.g. student grade, salary, social
security number, account balance, company name)
• Data Elements are combined into records or data structures,
where a Record is a meaningful combination of related data
elements that is included in a data flow or data store
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
13
Data Dictionary: Documenting Data Elements
ANALYSIS: Data & Process Modeling
•
•
•
•
•
•
•
•
•
•
•
•
Data Element Name / Label
Alternate Names
Type & length
O/P format
Default value
Prompt, Column header, or Field Caption
Source
Security
Responsible user(s)
Acceptable values & data validation
Derivation formula
Description / Comments
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
14
Data Dictionary: Documenting Data Flows
ANALYSIS: Data & Process Modeling
•
•
•
•
•
•
•
Data flow Name / Label
Alternate Names
Description
Origin / Source
Destination
Record
Volume & frequency
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
15
Data Dictionary: Documenting Data Stores
ANALYSIS: Data & Process Modeling
•
•
•
•
•
•
•
Data Store Name / Label
Alternate Names
Description
I/P Data flows
O/P Data flows
Record
Volume & frequency
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
16
Data Dictionary: Documenting Processes
ANALYSIS: Data & Process Modeling
•
•
•
•
•
•
Process Name / Label
Purpose / Description
Process Number
I/P Data flows
O/P Data flows
Process Description
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
17
Data Dictionary: Documenting External Entities
ANALYSIS: Data & Process Modeling
•
•
•
•
•
External Entity Name
Alternate Names
Description
I/P Data flows
O/P Data flows
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
18
Data Dictionary: Documenting Records
ANALYSIS: Data & Process Modeling
•
•
•
•
Records or Data Structure Name
Alternate Names
Definition / Description
Record content or composition
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
19
Object Oriented Concepts: Overview
ANALYSIS: Object Modeling
• Object Oriented analysis describes IS by identifying things
called objects that can represent a real person, place, event or
transaction (e.g. patient makes appointment with a doctor: all 3
are objects)
• The Object Oriented analysis is a new approach that sees a
system from the viewpoint of the objects themselves as they
function & interact with system
• The end product of Object Oriented analysis is an Object
Model, which represents the IS in terms of Objects & Object
Oriented concepts
• The main benefit of Object Oriented approach is using objects
and program code modules that can be reused
• Structured Analysis modeling using DFDs treated data &
processes separately, while in Object Oriented analysis,
Objects include data & the processes that affect that data;
Attributes that characterize the object & Methods that the
object performs when it receives a message
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
20
Object Oriented Concepts: Objects
STUDENT Object
ANALYSIS: Object Modeling
STUDENT
Characteristics
that describe
the STUDENT
Object
Tasks that the
STUDENT
Object can
perform
Copyright © 2003 Abou-Bakr Zayd
Attributes
Student Number
Name
Telephone
Date of Birth
Fitness Record
Status
Methods
Add fitness class
Drop fitness class
Change telephone
Change status
Update fitness record
Instances of
the STUDENT
Object
970075
Soha Sayed
0105005000
10-10-80
X
Current
Encapsulation means
that all data & methods
are self contained
making the object
appear as a black box
BIS Analysis
21
Object Oriented Concepts: Objects
INSTRUCTOR Object
ANALYSIS: Object Modeling
INSTRUCTOR
Characteristics
that describe the
INSTRUCTOR
Object
Tasks that the
INSTRUCTOR
Object can
perform
Copyright © 2003 Abou-Bakr Zayd
Attributes
Instructor Number
Name
Telephone
Fitness Class taught
availability
Status
Instances of the
INSTRUCTOR
Object
101
Zaki Morad
0101001000
Aerobics
Part Time
Current
Methods
Teach fitness class
Change telephone
Change availability
Change status
BIS Analysis
22
Object Oriented Concepts: Objects
Fitness Class Schedule Object
ANALYSIS: Object Modeling
FITNESS CLASS SCHEDULE
Attributes
Fitness Class Number
Date
Time
Type
Location
Instructor Number
Max Enrollment
Methods
Add fitness class
Delete fitness class
Change date
Change time
Change Instructor
Change Location
Change Enrollment
Copyright © 2003 Abou-Bakr Zayd
Registration Record Object
REGISTRATION RECORD
Attributes
Student Number
Fitness Class Number
Registration Date
Fee
Status
Methods
Add Student
Drop Student
Notify Instructor of add
Notify Instructor of drop
Notify all of fitness-class
cancellations
BIS Analysis
23
Object Oriented Concepts: Attributes
STUDENT Object
ANALYSIS: Object Modeling
State
Status
Future Registered but has not started to attend
Current Registered attending 1 or more classes
Past
Attended 1 or more classes in the past
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
24
Object Oriented Concepts: Methods
ANALYSIS: Object Modeling
Method:
Add
Student
Steps
1. Add new student instance
2. Record student number
3. Record student name
4. Record student telephone
number
5. Record student date of birth
6. Record sex of student
7. Record state of student
8. Save new student data
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
25
Object Oriented Concepts: Messages
STUDENT
ANALYSIS: Object Modeling
Message: ADD
tells the
STUDENT class
to perform all the
steps needed to
add a STUDENT
instance
Message: DELETE
tells the STUDENT
class to perform all
the steps needed to
delete a STUDENT
instance
Copyright © 2003 Abou-Bakr Zayd
Attributes
Student Number
Name
Telephone
Date of Birth
Fitness Record
Status
Methods
Add student
Delete student
Add fitness class
Drop fitness class
Change telephone
Change status
Update fitness record
Polymorphism is the
concept when a
message gives different
meanings to different
objects
BIS Analysis
26
Object Oriented Concepts: Classes
Car
ANALYSIS: Object Modeling
VEHICULE
Attributes
Attributes
Common
Attributes
Common
Methods
Make
Model
Year
Weight
color
Methods
Truck
Attributes
Uncommon
Attributes
Load Limit
Start
Stop
park
School Bus
Attributes
Uncommon
Attributes
Emergency Exit Location
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
27
Relationship among Objects & Classes: Dependency
Dependency
ANALYSIS: Object Modeling
School Bus
Attributes
Bus Number
Route Number
Start Time
Finish Time
Driver
Methods
Pick Up
Drop Off
Copyright © 2003 Abou-Bakr Zayd
Bus Route
Attributes
Follows
Route Number
Stop Number
Stop Location
Stop Time
Passengers
Methods
Add Stop
Delete Stop
Change Time
BIS Analysis
28
Relationship among Objects & Classes: Association
Association
ANALYSIS: Object Modeling
Student
Registration Record
Attributes
Student Number
Name
Telephone
Date of Birth
Fitness Record
Status
Methods
Add Student
Delete Student
Add fitness class
Drop fitness class
Change telephone
Change status
Update fitness record
Copyright © 2003 Abou-Bakr Zayd
Attributes
Adds/Drops
Fitness
Class
Student Number
Fitness Class Number
Registration Date
Fee
Status
Methods
Add Student
Drop Student
Notify Instructor of add
Notify Instructor of drop
Notify all of fitness-class
cancellations
BIS Analysis
29
Relationship among Objects & Classes: Aggregation
Aggregation
ANALYSIS: Object Modeling
Employee
Department
Attributes
Name
Date of Birth
Social Security Number
Telephone
Hire Date
Title
Pay Rate
Department
Methods
Get Hired
Terminate
Change Department
Copyright © 2003 Abou-Bakr Zayd
Attributes
Belongs To
Department Number
Department Name
Budget Code
Department Head
Employees
Methods
Prepare Budget
Hire Employees
Develop Plans
BIS Analysis
30
Relationship among Objects & Classes: Inheritance
Inheritance
ANALYSIS: Object Modeling
Employee
Attributes
Social Security Number
Telephone
Hire Date
Title
Pay Rate
Instructor
Attributes
Type of instructor
Social Security Number
Telephone
Hire Date
Title
Pay Rate
Methods
Methods
Get Hired
Get Fired
Change Telephone
Copyright © 2003 Abou-Bakr Zayd
Get Hired
Get Fired
Change Telephone
BIS Analysis
31
UML: Use Case Modeling
ANALYSIS: Object Modeling
<<uses>>
Student
Add Fitness Class
Produce Fitness
Class Roster
<<uses>>
Instructor
Change Availability
Update Instructor
Information
Use Case Modeling Examples
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
32
UML: Use Case Modeling
Add New Student Use Case
ANALYSIS: Object Modeling
Add New Student
Name:
Add New Student
Actor:
Student/Manager
Description:
Successful
Completion:
Alternative:
Describes the process used to add a student to a fitness class
1. Managers Checks Fitness-Class Schedule object for availability
2. Managers notifies student
3. Fitness-Class is open and student pays fee
4. Manager registers student
1. Managers Checks Fitness-Class Schedule object for availability
2. Fitness-Class is full
3. Managers notifies student
Precondition: Student requests fitness class
Postcondition: Describes the process used to add a student to a fitness class
Assumptions: None
Use Case Description to document the process
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
33
UML: Use Case Diagrams
ANALYSIS: Data & Process Modeling
Notifies
Adds
Add Fitness Class
Get
Assigned
Notifies
Student
Instructor
Add Instructor
Notifies
Check
and
update
Manager
Copyright © 2003 Abou-Bakr Zayd
Notifies
Notifies
Change Schedule
Use Case Diagram
a visual summary of
several related use
cases within a
system or
subsystem
BIS Analysis
34
UML: Class Diagrams
ANALYSIS: Data & Process Modeling
Sales Manager
1
Manages
0..*
Attributes
0..*
Sales Rep
Attributes
Assigned to
Methods
1
Manages
1
Sales Office
1
Places
Methods
1
Assigned
0..*
1
Customer
Attributes
Attributes
Methods
Methods
0..*
Order
Attributes
Methods
Copyright © 2003 Abou-Bakr Zayd
Includes
0..*
Items Ordered
1..*
Class Diagrams
a detailed view of a
single use case, and
the relationship
among the classes
Attributes
Methods
BIS Analysis
35
UML: Sequence Diagrams
ANALYSIS: Data & Process Modeling
Student
Fitness-Class
Schedule
Manager
Request
Fitness-Class
Registration
Record
Check
Notify
Focus
Pay
Register
Messages
Sequence Diagrams: a dynamic
model of a single use case,
showing interaction among
classes during a specified time
period
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
36
UML: State Transition Diagrams
ANALYSIS: Data & Process Modeling
Attends
Fitness-Class
Enrolls
Future
Current
Drops Fitness-Class
Drops Fitness-Class
Inactivity for
12 months
Past
Fitness-Class Canceled
State Transition Diagram:
shows how an object changes
from one state to another,
depending on events that affect
the object
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
37
UML: Activity Diagrams
ANALYSIS: Data & Process Modeling
Customer
needs cash
Customer
inserts
ATM card
Card is
accepted
PIN is
Customer
accepted
enters PIN
Customer
requests
cash
Sufficient funds available
ATM
adjusts
balance
ATM
provides
cash
Sufficient funds not available
ATM
notifies
customer
Copyright © 2003 Abou-Bakr Zayd
Activity Diagrams: resembles a
horizontal flow chart that shows
the actions & events as they
occur, their order and outcomes
BIS Analysis
38
Completion of Systems Analysis:
ANALYSIS: Data & Process Modeling
• Systems Requirements Document:
– contains the requirements for the new system, describes the alternatives
that were considered and makes a specific recommendation to
management.
– This important document is the starting point for measuring the
performance, accuracy & completeness of the finished system before
entering the system design phase
– It represents the contract that identifies what must be delivered by
system developers to users
• Presentation to Management
– Begin with purpose & primary goals & objectives of the system
– Summarize the primary viable alternatives including cost, advantages &
disadvantages
– Chosen alternative and explanation
• Management decision:
–
–
–
–
–
Develop in-house system
Modify current system
Purchase / customize S/W package
Perform additional systems analysis work
Stop all further work
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
39
Transition to Systems Design
ANALYSIS: Data & Process Modeling
• The transition from systems analysis to design is the transition
from the logical design to the physical design of the system
• Logical Design (conceptual design or essential model): defines
the functions & features of the system and the relationships
among its components. It includes the system’s O/P produced,
I/P needed, and processes performed without regard to how
tasks will be accomplished physically and methods of
implementation (What? Completed in Analysis Phase)
• Physical design (functional design): is a plan for the actual
implementation of the system. It is built on the system’s logical
design and describes the implementation of a specific set of
systems components (How? Completed in Design Phase)
• Logical & Physical Design are closely related as good systems
design is impossible without careful & accurate systems
analysis. In fact, the design phase typically cannot begin until
analysis work is complete
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
40
• H. Deitel, P. Deitel & K. Steinbuhler, e-Business and eCommerce for Managers, 2001
ANALYSIS: References
• G. Shelly, T. Cashman & H. Rosenblatt, Systems Analysis and
Design (4th), 2000
• J. Whitten, L. Bentley & K. Dittman, Systems Analysis and
Design Methods (5th), 2000
Copyright © 2003 Abou-Bakr Zayd
BIS Analysis
41