Do’s & Don’ts of DFDs

An easy mistake….

RecordPaymentdetails

Customer

Create Bank

Depositdata

Accountsdepartment

Bank

Sends payment details

Payment Data moves

Sends receipt details

Payment Data moves Deposit Data

movesCredit Data moves

Customerdatabase

An easy mistake… easily put right

RecordPaymentdetails

Customer

Create Bank

Depositdata

Accountsdepartment

Bank

Sends payment details

Payment Data moves

Sends receipt details

Payment Data moves Deposit Data

movesCredit Data moves

Customerdatabase

Update Customerdatabase

DMU Bank - Executive Loans departmentA salesperson calls in with a proposed deal.

The call gets taken by the first available clerk, who logs it and writes the details down.

They take the details to another clerk who enters the data into a computer, and checks the client’s creditworthiness.

This person writes down the details and takes them to the loan officer.

The loan officer then modifies the standard DMU agreement. This person uses a PC with word processing, not a mainframe terminal.

Details of the modified agreement, together with the other documents, are sent to another desk, where another clerk decides on the interest rate. This clerk uses a terminal, but a different application on the mainframe.

All the papers are then carried to the word processing section, where the quote letter is generated.

Finally the letter is sent back to the salesperson overnight.

1. How many processes are there?

2. How many data stores are there?

3. How many sources / sinks are there?

The Executive Loan Process

4Determine

InterestRate

1Log

Request

3ModifyLoan

Agreem’t

5Create Quote Letter

2CheckCredit

Salesperson

SalespersonCreditFiles

InterestFiles

The Executive Loan - Process or Mess?• So what do you suggest?• Clue 1 - How many people do you need?• Clue 2 - How many computer systems do you

need?

ProcessContract

Salesperson

Specialists

CreditFiles

InterestFiles

Request

Rate

Return

SupportingDataStatus

And where did that really come from?

IBM Credit Corporation

Hammer & Champy (1993)

• Welcome to BPR -

Business Process Reengineering

Do’s and Don’t’sDON’T DO

Do’s and Don’t’s

A

B

A

A

DON’T DO

Do’s and Don’t’s

Customer

DON’T DO

Send to Customer

Enter in Log

EnterCustomer

DetailsVerb

LogNoun

CustomerNoun

Decomposition and Balancing

1.0Food

Orderingsystem

Customer

Restaurant Manager

Kitchen

Decomposition and Balancing

1.1Receive &Transform

Food Order

Customer Kitchen

2.1Update GoodsSoldFile

3.1UpdateStockFile

4.1Produce

ManagementReports

Restaurant Manager

D1 StockFile

D2 Goods Sold File