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Systems Analysis and DFDs. Systems Life Cycle concept. Systems Analysis. determines the CONTENT of an MIS represents 25% of the MIS development effort relates to performance higher budget compliance higher satisfaction. Importance of Systems Analysis. Data flow diagram (DFD).
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determines the CONTENT of an MIS • represents 25% of the MIS development effort • relates to performance • higher budget compliance • higher satisfaction Importance of Systems Analysis
How to factor a system? Leveling DFDs • 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
Second level purchase order accounts payable vendor account accounts invoice check 3.0 2.0 1.0 due write revise Invoice Vendor Vendor vendor balance approval checks due checking account payable invoices
