1 Phase 3 :Systems Design The next step of the cycle is to design the new system. Of all the linear...

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Phase 3 :Systems DesignThe next step of the cycle is to design the new system.

Of all the linear cycle phases, design is the hardest phaseto describe. It is very different from analysis. In analysisit is possible to come up with a correct model of theexisting system. There is, however, no such thing as acorrect design. It is even harder to define the best designfor a given system. A good design is very dependent on aparticular system, and what is a good design for onesystem may be bad for another. It is not possible topropose a set of standard solutions from which you

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can select a good design for any system. Instead, design

requires considerable creativity to make the necessary

system-specific changes and additions and come up with

a new system that is acceptable to users and easy to

implement.Output designDuring The systems design phase, we design an

information system that satisfies the requirements thatwere specified in the system requirements documentduring the system analysis phase.Next, we discuss design techniques and strategies

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for the output component of an IS; specifically, weexamine design techniques and strategies for printedreports, screen output, and other systems outputs. Systems design overview

• Logical DesignThe logical design of an IS defines the logical or

conceptual relationships among the components of the IS.

A logical design defines all the input available to the

system, all the outputs that must be produced by the

system, and all the processes that must be performed to

meet the defined system requirements independent of how

they will be physically accomplished.

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Logical Design

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• Physical design The physical design of an IS is concerned with

the actual physical implementation of the logicaldesign. • Phase iterations

The phases in the SDLC are sometimes said to beiterative. Man IS professionals say that you iteratebetween analysis and design, repeating and refining,until an effective physical design is developed.A system analyst should never expect to return to aprevious phase.

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Physical Design

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• Systems design activities• Review the system requirement• Design the system

• Design the systems output• Design the systems input• Design the systems files and database• Design the systems processing• Design the software

• Present the system design

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General guidelines for systems designThe goal of the systems design effort is to design

an IS that will be effective, reliable, and maintainable.To be effective, the system must satisfy the definedrequirements and meet the specified constraints. But asystem that is not used cannot be effective. Aneffective system is one that the end users accept andactually use.

The reliability of an IS relates to how the systemreacts to errors, whether they are input data errors,processing errors, hardware failures, or human mistakes. A more realistic approach for system

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reliability is for the system to plan for errors, detectthem when they first occur, and allow for theircorrection.

An IS has maintainability if it is simple, flexible,and easy to modify. Modifications will be necessary tocorrect errors in the system, to adapt the system tochanging end user requirements, or to enhance thesystem to add capabilities or to take advantage ofchanging technology. Your systems design must be flexible enough to accommodate future modifications.

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• Design tipsThe following tips will help you design effective,

reliable, and maintainable information systems. Tomake them easier to use, we have classified these tipsby end user considerations, data considerations, andprocessing considerations.End user considerations

• Consider point where end users interact with the system• Anticipate future end user needs

Data considerations• Enter data where and when it occurs• Verify data when it is input

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• Use automated data entry methods whenever possible• Control access for data entry• Report every instance of entry and change to data • Enter data only once• Avoid duplicating data in data stores

Processing considerations• Choose the simple solution• Create independent modules that perform a single function

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Output design introductionThe primary output media for an IS are printers

and screens, but several other media are used to outputInformation, output device:

• Printer• Screen : monitor, CRT, or VDT• Plotter• Computer output microfilm (COM)• Voice• Specialized device : point-of-sale terminals, ATMs

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Designing printed reportsReports are classified by their content and by

their distribution. The classification by content includesdetail, exception, and summary report, whereas theclassification by distribution includes internal andexternal reports.• Reports classified by content

• Detailed Reports• Exception Reports • Summary Reports• Analytical Reports• Historical Reports

14Detail Report

September 5, 1998 Student and Course Report Page 1 of 348 Fall Semester 1998

Last, First Name Student ID Course ID Units SectionAdams, Mary

Aherns, Madhi

Banks, Jamal

387-33-8610

559-68-0348

371-49-3256

Bio101Eng100Soc105Phl108Eco104Total

Act102Bio101Chm109Phl108PEd118Total

Chm109Eco104Eng100MIS111Mkt114Soc105Total

3 3 3 3 315

3 3 3 3 113

3 3 3 3 3 318

21113

12215

121211

15Detail Report

16Detail Report

17Exception Report: Only those employees who have worked overtime are include in the report

18Exception Analytical Report

San Diego Weather Exception ReportFor Calendar Year 1997

Lower Limit: 45 degrees; Upper Limit: 85 degrees

1/9/98

Date Time of Day Temperature01/11/97

01/12/97

01/13/97

02/08/97

02/26/97

03/14/97

07/19/97

07/20/97

07/21/97

etc...

04:15am

04:12am

04:11am

03:50am

03:40am

02:57am

02:45pm

02:38pm

02:30pm

etc...

42

41

41

39

40

44

89

94

95

etc...

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A summary report lists subtotals and grand totals.

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Summary Report

September 5, 1998 Course Summary Report Page 1 of 28 Fall Semester 1998

Course ID Course Name Units Sects Enroll Enroll/Sect 3...... 3...... 3...... 3...... 3...... 3...... 3...... 1

300......600......90......60....208......330......110......84

Act102......Bio101......Chm109......Eco104......Eng100......MIS111......Mkt114......PEd118

Accounting Prin.......Intro to Biology......Organic Chem.......Macro Economics......Begin. English......Intro to Computers......Prin. of Marketing......Begin. Golf

Total Total Avg.

4....6....2....2....8....3....2....7

75......100......45......30....26......110......55......12

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Horizontal Analytical Report

Data Based Decisions, Inc.Comparative Balance Sheet - Horizontal Analysis

For Fiscal Years 1996 and 1997 - values in millions

1996 1997 Amount PercentAssets Cash Accounts Receivable Office EquipmentTotal Assets

Liabilities Accounts Payable Long-Term DebtTotal Liabilities

Capital Common Stock Retained EarningsTotal Capital

Total Liabilities & Capital

1/27/98

0.63.35.29.1

1.13.24.3

3.01.84.8

9.1

$ 0.8 3.7 5.510.0

1.2 2.8 4.0

3.0 3.0 6.0

10.0

$ $Difference Difference

0.2 0.4 0.3 0.9

0.1(0.4)(0.3)

0.0 1.2 1.2

0.9

33.0 %12.1 5.8 9.9

9.1(12.5) 7.0

0.066.725.0

9.9

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Vertical Analytical ReportData Based Decisions, Inc.

Comparative Income Statement - Vertical AnalysisFor Fiscal Years 1996 and 1997 - values in millions

-----------1996-------- ----------1997-----------Income: Hardware Sales Software Sales Supplies Sales Consulting ServicesTotal Income

Expenses: Advertising Office Salaries Hardware Software SuppliesTotal Expenses

Net Income before taxesIncome Taxes

Net Income

1/27/98

1.61.20.24.47.4

0.20.33.30.90.70.15.5

1.90.8

1.1

$ 21.6 16.2 2.7 59.5100.0

2.7 4.1 44.6 12.2 9.5 1.4 74.5

25.5 10.8

14.7

$

Amount Percent Amount Percent

1.9 1.7 0.3 5.2 9.1

0.3 0.4 3.9 1.1 1.2 0.2 7.1

2.0 0.9

1.1

20.9 18.7 3.3 57.1100.0

3.3 4.4 42.9 12.1 13.2 2.2 78.1

21.9 9.9

12.0

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Counterbalance Analytical Report

Data Based Decisions, Inc.North Island Networking Project Analysis

Project Start Date: 10/1/98 - ($000 omitted)

Income: Hardware Sales Software Sales Supplies Sales Consulting ServicesTotal Income

Expenses: Project Overhead Salaries Hardware Software SuppliesTotal Expenses

Net Income on the project

8/12/98

800 300 050 1501,300

200 140 750 200 401,330

(30)

$ $

Worst Case Moderate Case Best Case

800 300 050 1751,325

200 140 700 180 401,260

65

850 350 050 1901,440

200 150 650 160 401,200

240

$

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Variance Analytical Report

Student Personal Monthly BudgetVariance Analysis

Month: October 1997

11/9/97

$ $$Income

Expenses Rent Telephone Car Payment Insurance Food/Drink Clothes School Supplies Savings Utilities Gifts DiscretionaryTotal Expenses

Balance Remaining

Budget Actual Variance700

150 20100 70135 50 25 50 25 25 50700

0

680

150 24100 70145 38 8 50 28 35 55703

(23)

(20)

(4)

(10)1217

(3)(10)(5)(3)

(23)

(2.9%)

(20%)

(7.4%)24%68%

(12%)(40%)(10%)(0.4%)

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• Reports classified by distribution• Internal reports• External reports• Turnaround report

September 5, 1998 Course Summary Report Page 1 of 28 Fall Semester 1998

Course ID Course Name Units Sects Enroll Enroll/Sect 3...... 3...... 3...... 3...... 3...... 3

300......600......90......60....208......330

Act102......Bio101......Chm109......Eco104......Eng100......MIS111

Accounting Prin.......Intro to Biology......Organic Chem.......Macro Economics......Begin. English......Intro to Computers

Total Total Avg.

4....6....2....2....8....3

75......100......45......30....26......110

Inte

rnal R

ep

ort

Sam

ple

s

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21113

12215

3 3 3 3 315

3 3 3 3 113


Act102Bio101Chm109Phl108PEd118Total

387-33-8610

559-68-0348

371-49-3256

Adams, Mary

Aherns, Madhi


Last, First Name Student ID Course ID Units Section

Internal Report Samples

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ABC IncorporatedSALES ORDER FORM

Order Number Order Date

Customer Number

Customer Name

Street Address

City State Zip Code

Product Product Unit Total Number Name Color Price Quantity Price

1

2

3

4

5

6

7

ORDER TOTAL

SALES TAX

SHIPPING

GRAND TOTAL

Come to ABC Incorporated forall your technology needs.

Thank you for your patronage.

You are a valued customer.

External Report Sample

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• Report design considerationsTo design the actual physical format of a printed report,You use a printer spacing chart. Printer spacing chartsprovide a standardized method for visuallydocumenting a report format; programmers use themwhen writing the program to produce the report.• Report volume calculationsDuring the systems analysis phase, you estimated thesize of every printed report. System analysts andmanagement use these volume calculations to decide ifadditional printers must be purchased.• Report approvalsThe end users must approve every report design.

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Output Design with an Old Style Printer Spacing Chart

30A printer spacing chart and report sample

31A printer spacing chart and report sample

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Five different column heading alignment options.

33The Employee Hours report is a detail report with control breaks.

34An improved version of Employee Hours report

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Designing screen outputScreen output is very important to business

organizations. Today, most people in an organizationhave ready access to a VDT or personal computer, youfind computer workstations everywhere from shopfloors and loading docks to executive offices. Screenoutput offers several advantages over printed output. Most importantly, screen output is timely.• Screen design considerations• Character output• Graphical output• Special video effects

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Quit Report

Commandbutton

38Output Format Examples

a)

zoned

b) graphic

c) narrative

21113

12...

3 3 3 3 315

3 3...


Act102Bio101…..

387-33-8610

559-68-0348

Adams, Mary

Aherns, Madhi, Jamal


Last, First Name Student ID ourse ID Units Section

1s 3r0

100

1s 3r

0

50

100

1stQtr

2ndQtr

3rdQtr

4thQtr

Output formats.Today's information systems present information in three basic formats--zoned, graphic, and narrative asillustrated in Figure 9.3. Format refers to the look of the output on the media, hence sound is not included here.Zoned output is the traditional row and column oriented textual and numeric information. Graphic output...

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OUTPUT DESIGN

•SCATTER DIAGRAM

•LINE DIAGRAM

•BAR CHART - horizontal &

vertical

•SECTOGRAPH - pie & layer

OUTPUT GRAPHS

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data sets:

A B C D

X Y X Y X Y X Y1081713459111915

5713103611141712

810913141146712

8988893679

6131115210178514

91412156111610714

17191218142013151116

861371151210149

A

0 5 10 15 20

20

15

10

5X

Y

..

..

.

.

.

..

.

B

0 5 10 15 20

20

15

10

5

Y

X

. .. ......

.

C

0 5 10 15 20

20

15

10

5

Y

X

. . .. . .

....

D

0 5 10 15 20

20

15

10

5

Y

X

......

....

Scatter Diagrams

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Line Diagram

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Computers Unlimited, Inc.Sales of Hardware and Software

For Year 1997 in Dollars

200

175

150

125

100

75

50

25

0

Hardware

Software

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Vertical Bar Chart

California State University, PasadenaCollege of Business Administration

Total Enrollment by Semester

Fall Spring Fall Spring Fall Spring Fall Spring‘94 ‘95 ‘95 ‘96 ‘96 ‘97 ‘97 ‘98

500

450

400

350

300

250

200

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Pie Chart

Accounting24%

Finance22%Information

Systems18%

Management20%

Marketing16%


Enrollment by Major - Fall 1997

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Layer Graph


Total Enrollment by Semester

Spring Fall Spring Fall Spring ‘96 ‘96 ‘97 ‘97 ‘98

350

300

250

200

150

100

50 Accounting

Finance

Information Systems

Management

Marketing

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3 Dimensional (3D) Horizontal Bar Chart


Enrollment by Major - Fall 1997

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Designing other outputs• Tapes, disks, and diskettes• Other output media

Output controlThe topic of output control encompasses all measuresnecessary to ensure that output information is correct,complete, and secure.

Output security is concerned with protecting theprivacy rights of individuals and organizations, as wellas protecting the company’s proprietary data from theftor unauthorized access.

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OUTPUT DESIGN

•Accessibility - how easy is it to

use?•Timeliness - is it available in time?

•Relevance - is it helpful?•Accuracy - is it error-free?•Usability - is it in an acceptable format?

What factors contribute to high quality, useable information?

1 Phase 3 :Systems Design The next step of the cycle is to design the new system. Of all the linear...

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Transcript of 1 Phase 3 :Systems Design The next step of the cycle is to design the new system. Of all the linear...