1. REQUIREMENTS ANALYSIS
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2. Context of System Analysis

3. Requirements Analysis
The process and technique that a group of system analyst uses to identify, analyze, and understand system requirements
System’s requirements specify what the information system must do, or what property or quality the system must have.
One of the early IS development phases.
Data Model: the most part of requirements analysis phase for DB System Development
No additional notes.

4. Requirements Analysis for RDS development
Identify essential information
for finding entity, attribute, cardinality…..
Remove redundant, unimportant details
To comply with the theories of RDS
Clarify unclear natural language statements
Such as interview documents with clients
Distinguish data and operations
Data: ERD (entity relationship diagram)
Operation: DFD (data flow diagram)

5. Relative Cost to Fix an Error

6. Relative Cost to Fix an Error (BASED ON CONSULTANT REPORTS & TRADE LITERATURE)1 2 3 4 5
COSTS
ANALYSIS AND DESIGN
PROGRAMMING
CONVERSION
POSTIMPLELENTATION

7. Results of Incorrect Requirements Analysis
The system may cost more than projected
The system may be delivered later than promised.
The system may not meet the users’ expectations and that dissatisfaction may cause them not to use it.
Once in production, the costs of maintaining and enhancing the system may be excessively high.
No additional notes.

8. Very Difficult to Manage
Over the lifetime of the project, it is very common for new requirements to emerge and existing requirements to change.
Studies have shown that over the life of a project as much as 50 percent or more of the requirements will change before the system is put into production.

9. System Development is about Documentation…….
Data model is part of an official DB document (blue print of the DB)
Department of Justice
System development is about “documentation….. Documentation…… documentation”
See the Department of Justice SDLC documentation on the course website

10. Information Systems Architecture
Data
Architecture
Process
Architecture

11. IS Architecture Can be divided into data and process architectures
Data architecture by Data Model
ERD: focus on the optimal organization of data, not on where or how data are used
Process architecture by Process Model
DFD (Data Flow Diagram): focus on how and when data are moved
Diagram for IS architecture
UCD (Use Case Diagram)

12. How to develop IS Architecture?
How the foundation of IS architecture should be developed?
Strategic Management
Mission statement: root of strategic Mngt.
Corporate Strategy
IS Strategy
IS architecture (UCD)
Data (ERD) and Process (DFD) Architectures

13. What is Strategic Management?
Highest level of overall planning
is the continuous planning, monitoring, analysis, and assessment of all that is necessary for an organization to meet its goals & objectives and to position a firm to succeed in its market environment.

14. Strategic Management Process (con’t)
Components of Strategic Management Process
Strategic Management Process (4:35)
Website: Strategic Management Process

15. What is Use Case Diagram?
The UCD is for the modeling of real-world objects and systems.
It is a graphic depiction of the interactions between stakeholders and a system
Focus on “What a system does”…”rather than how a system does.”
In other words, it is a methodology used in system analysis to identify, clarify, and organize OVERALL SYSTEM REQUIREMENTS.

16. UCD for Bank ATM
Chapter 7 - Modeling System Requirements With Use Cases

17. What is Data Flow Diagram?
A DFD is a graphical representation of the "flow" of data through an information system, modelling its process aspects.
How data enter a system and transformed in that system
A DFD is often used as a preliminary step to create an overview of the system without going into great detail, which can later be elaborated.

18. Creating Data Flow Diagram Lemonade Stand Example

19. Creating Data Flow Diagrams
Example
Steps:
The operations of a simple lemonade stand will be used to demonstrate the creation of data flow diagram.
Create a list of activities
Construct Context Level DFD (identifies sources and sink)
Construct Level 0 DFD (identifies manageable sub processes )
Construct Level 1- n DFD (identifies actual data flows and data stores )

20. Creating Data Flow Diagrams
Example
Create a list of activities
Think through the activities that take place at a lemonade stand.
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

21. Creating Data Flow Diagrams
Example
Construct Context Level DFD (identifies sources and sink)
Create a context level diagram identifying the sources and sinks (users).
Context Level DFD
Sales Forecast
CUSTOMER
0.0
Lemonade System
EMPLOYEE
Order
Production Schedule
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
Product Served
Pay
Payment
Time Worked
Received Goods
Payment
Purchase Order
VENDOR

22. Creating Data Flow Diagrams
Example
Construct Level 0 DFD (identifies manageable sub processes )
Create a level 0 diagram identifying the logical subsystems that may exist.
Level 0 DFD
1.0
Sale
Sales Forecast
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
Customer Order
Product Ordered
CUSTOMER
Payment
2.0
Production
EMPLOYEE
Production Schedule
Product Served
Inventory
Received Goods
VENDOR
3.0
Procure-ment
Purchase Order
Order Decisions
Payment
Pay
Time Worked
4.0
Payroll

23. Creating Data Flow Diagrams
Example
Construct Level 1- n DFD (identifies actual data flows and data stores )
Create a level 1 decomposing the processes in level 0 and identifying data stores.
Level 1 DFD
CUSTOMER
Customer Order
Request for Forecast
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
ORDER
1.1
Record Order
1.3
Produce Sales Forecast
Severed Order
Payment
Sales Forecast
1.2
Receive Payment
PAYMENT

24. Process Decomposition
1.0
Sale
1.1
Record Order
1.2
Receive Payment
2.0
Production
2.1
Serve Product
2.2
Produce Product
2.3
Store
Product
0.0
Lemonade System
3.0
Procure-ment
3.1
Produce Purchase Order
3.2
Receive Items
3.3
Pay Vendor
4.0
Payroll
4.1
Record Time Worked
4.2
Calculate Payroll
4.3
Pay Employee
Context Level
Level 0
Level 1

25. Why not using Flow Chart?
Complex Logic:
Many of today’s MIS program logic is quite complicated. In that case, flowchart becomes complex and clumsy because the complexity can grow exponentially.
Not so recommendable in MIS & CS
Alterations and Modifications:
If alterations are required the flowchart may require re-drawing completely. This is quite time and effort-consuming.

26. Why not using Flow Chart?
Reproduction:
As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem.
The essentials of what is done can easily be lost in the technical details of how it is done.
Factors that affect the sequence are not included.