Do’s & Don’ts of DFDs

An easy mistake…. Customer Sends payment details Record Payment Create Bank Deposit data Accounts department Sends payment details Payment Data moves Sends receipt details Deposit Data moves Credit Data moves Customer database

An easy mistake… easily put right Record Payment details Customer Create Bank Deposit data Accounts department Sends payment details Payment Data moves Sends receipt details Deposit Data moves Credit Data moves Update Customer database Customer database

DMU Bank - Executive Loans department A 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 Salesperson Interest Files 1 Log Request 4 Determine Interest Rate 2 Check Credit 3 Modify Loan Agreem’t 5 Create Quote Letter Credit Files Salesperson

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? Request Rate Return Supporting Data Status Salesperson Interest Files Process Contract Specialists Credit Files

And where did that really come from? IBM Credit Corporation Hammer & Champy (1993) Welcome to BPR - Business Process Reengineering

Do’s and Don’t’s DON’T DO

Do’s and Don’t’s DON’T DO A B A

DON’T DO Do’s and Don’t’s Verb Noun Noun Customer Enter Customer Details Verb Enter in Log Log Noun Send to Customer Customer Noun

Decomposition and Balancing 1.0 Food Ordering system Customer Restaurant Manager Kitchen

Decomposition and Balancing 1.1 Receive & Transform Food Order Customer Kitchen 2.1 Update Goods Sold File 3.1 Stock 4.1 Produce Management Reports Restaurant Manager D1 Stock D2 Goods Sold File