1. Systems Analysis and DFDs

2. Systems Life Cycle concept

3. Systems Analysis

4. Importance of Systems Analysis
determines the CONTENT of an MIS
represents 25% of the MIS development effort
relates to performance
higher budget compliance
higher satisfaction

5. Data flow diagram (DFD)

6. Leveling DFDs How to factor a system? The BLACK BOX concept:
you know the inputs it expects
you know the outputs it should give back
you know its function (what it does)
you do not need to know the specifics to use it
Controlling complexity of black boxes
each box should solve one well-defined piece of the problem
each box should be easy to understand
connections should be made as simple as possible

7. Exploding DFDs

8. National Merchandising Case

9. Second level purchase order vendor account accounts payable accounts
invoice
check
1.0
2.0
3.0
due
revise
write
Invoice
Vendor
vendor
Vendor
approval
balance
checks
due
payable invoices
checking account

10. Third level

11. Third level - continued

12. Third level - end