Transaction Processing Systems:The Need for Physical Design Methodology

Teaching

Paul Rosenthal

California State University, Los Angeles

Outline

• Importance of TPS Applications• Scope of TPS Applications• Recommended Physical Design Charting

Approach• Typical Physical Design Methodologies• Oversimplification of Design Examples

Transaction Processing Systems

• Transaction Processing Systems applications (TPS) are the core of information systems (IS) impact on the public.

• In the typical business organization, because of the number of clerical workers normally involved, they constitute the majority of IS project funding requirements.

A Typical Text’s View

Turban, McLean & Wetherbe (2004). IT for Management.

The True Scope of Transaction Processing Systems

Figure 1: Structure of Transaction Processing Systems

Backup

Data

Online TPSProcessing

(24/7)

Night-time BatchProcessing

Periodic BatchProcessing(Monthly)

MIS/DSS RetrievalSystem

ESS GraphicPresentation

Systems

Op's Data

InteractiveData

Log Data

Mgmt Data

CumulativeData

AnalysisData

MIS\DSSData

Warehouse

ESS Data

Customers et.

Clerks

Supervisors

InterfacingSystems

DailyReports

ESS AnalysisSystem

ExternalData

MonthlyReports

Executives

Planners

Managers

Staff/Researchers

FinancialSystems

CriticalSuccessFactors

The Need for Physical Design Methodology Teaching

For TPS, a physical design is created from a DFD based logical design, by separating processes and data stores by:

• time (daily vs. monthly, day vs. night ...), • place (client or server), • centralized vs. distributed..., • online vs. batch,

• manual vs. automated, etc.

A Term Project Architecture

A/P

KitchenTennisOffice

GolfOffice

Bar

Restaurant

Accounting

Reception/Membership

ManagersOffice

Onlineand

BatchOperations

Data

Statements etc..

MISData

Payments etc..

Country Club Architecture

Executive Offices

Store

AdHoc & Scheduled

MIS Reports

AS/400 (i5)

WAN

LAN

AccountingReportsQueries

Headquarters Architecture

Figure 2: Physical Level Process Design (Restaurant)

MembershipCard

Member Receptionist ScanCard

Process

New Tab Record

OrderSlip

toTableModule 1

Entry

Waitress

OrderSlip

OrderProcess

Module 2Ordering

Inser

t Ord

ers

intoT

ab R

ecor

d

KitchenOrder

BarOrder

Bar ItemsFood Item

s

Module 3Exiting

OrderEntry

Process

Member Receptionist

OrderSlip

BillingProcess

Receipt

Tab

Rec

ord

toMonthlyBilling

System

at Table

TabProcessing

System

ReceiptSignatureProcess

File

Priced Tab

Sign

Scan

Typical Physical Design Methodologies

Whitten (2004) - Their physical data flow diagram based method for an online system demonstrates:

• person/machine boundaries• network architecture • technology assignment• process distribution• data distribution

Typical Physical Design Methodologies

Pressman (2004) – diagrams a process view of the transition to design

Entity-Relationship

Diagram

Data FlowDiagram

State-TransitionDiagram

Data Dictionary

Process Specification (PSPEC)

Control Specification (CSPEC)

Data Object Description

THE ANALYSIS MODEL

proceduraldesign

interfacedesign

architecturaldesign

datadesign

THE DESIGN MODEL

Oversimplification of Design Examples

Partial Function Design

Enter Valid Card

Insert Password

Main Menu

Transfer FundsDeposit Funds InquiryWithdraw Funds

Bank Teller state transition diagram(Langer , page 72 )

C Enter Valid Bank Card

C Valid Password

C Invalid Card or “Time Out”

Invalid Password or “Time Out”C

C Select “Withdraw”C Select “Deposit”

C Select “Transfer”

C Select “Inquiry”

C Complete Activity

More Complete Online Scope

Recommended Bank Teller state transition diagram

A State

A Physical Transition

An Automated Transition

Proposed Symbolism

Validate Card

Validate Password

Main Menu

Transfer FundsDeposit Funds InquiryWithdraw Funds

Keyin Password

Valid Account

Select “Withdraw”Select “Deposit”

Select “Transfer”

Select “Inquiry”

Startup

Ejectif Invalid

Complete Activity

(A system originated action )

( A Customer originated action )

Welcome Screen

Insert Bank Card

Select “Done”

Oversimplification of Scope

Illustration of combined Online and Batch from S&C Chap 8

Shelly, Cashman & Rosenblatt (2006)

More Complete System Scope

POSTerminal

POSProgram(Online)

InventoryDatabase

CumulativeDaily SalesTransaction

File

End ofDay

Daily SalesProgram(Batch)

AccountingDatabase

Daily SalesReport

Physical Elements Added/Corrected

Standard USE Case Charting Method

CustomerCustomer

Enroll or updatemember

Enroll or updatemember

Rent videosRent videos

Find overduevideos

Find overduevideos

Return videosReturn videos

Charge creditcard

Charge creditcard

Purchasing System

ClerkClerkCredit Card Company

<<Include>><<Include>>

<<Include>>

<<Include>>

SystemBoundary

Actor

Use Case

Relationship

USE Case Diagram from V/S/P Chapter 8

Replace Incorrect Symbols

CustomerCustomer

Enroll or updatemember

Enroll or updatemember

Rent videosRent videos

Find overduevideos

Find overduevideos

Return videosReturn videos

Charge creditcard

Charge creditcard

ClerkClerk

<<Include>><<Include>>

<<Include>>

<<Include>>

SystemBoundary

Actor

Use Case

RelationshipInventorySystem

Credit CardCompany System