Example Data Flow Diagram

Generate Point Redemption Coupons Assume your assignment as an analyst is to take the 3.0 process and break it into smaller sub-processes

This figure from the text has an error, all processes MUST be numbered Data flows, sources, and sinks outside the boundary of the process will remain the same as we decompose the process into subprocesses

Additional Information The ‘Generate point redemption coupons’ process has several sub-processes The process ‘Separate into Categories’ takes the ‘Customer Activities’ data and classifies purchases as either ‘TV purchase or ‘Computer purchase’ or ‘Other purchase’ A TV purchase is checked to see if it is a TV suitable for a wall mounting, if so an instant coupon is created at the cash register and given to the customer A computer purchase causes an instant coupon to be generated for the customer to purchase additional memory – a file matching computer memory to computers is kept by Petrie Electronics All other sales go to a process that groups them by product group and updates the ‘Customer Activity Records’

Begin by including sources and sinks that cross the boundary Customer Activity Records Customer

Next add the sub-processes Customer Activity Records 3.2 If wall mounted, create coupon 3.1 Separate into categories 3.3 Create coupon for memory 3.4 Create totals by product group Customer

Next add any required data stores Customer Activity Records 3.2 If wall mounted, create coupon 3.1 Separate into categories 3.3 Create coupon for memory Memory Specifications 3.4 Create totals by product group Customer

Customer Activity Records Then add data flows and label them (remember that the data flows across the boundary cannot change) Customer Activity Records TV 3.2 If wall mounted, create coupon Coupons Customer Activities 3.1 Separate into categories Computer 3.3 Create coupon for memory Coupons Memory specifications All other activities Memory Specifications Coupon Information 3.4 Create totals by product group Customer

Check for errors

Customer Activity Records 3.2 If wall mounted, create coupon TV Coupons Customer Activities 3.1 Separate into categories Computer 3.3 Create coupon for memory Coupons Memory specifications All other activities Memory Specifications Coupon Information 3.4 Create totals by product group Customer