Member Avatar for batman13

I'm new to Daniweb so firstly greetings to all : )

I've just started learning how to use DFD, but have yet to rap my head around them. I have a example which I'm tying to figure out. I'm trying to do a level 0 of the following:


Keep track of which driver and which vehicle were used on a particular run.
Produce an invoice at the end of the month to be sent to the council.

At the start of each day the manager will allocate a vehicle and driver for each route. Sometimes the bus and driver will be used for the morning and afternoon runs but on other occasions different vehicles or drivers may be used.


The only process I can see for sure is producing an invoice for the council. I'd really appreciate any help.

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  • Latest Post Latest Post by aman007

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A few clarifications before you draw: a context diagram shows the whole system as one process with external entities; a Level‑0 DFD usually breaks that single process into its main subprocesses. As suggested, start by listing the data, where it comes from, what happens to it, and who receives the results. For this bus/run example the obvious external actors are the Manager (who allocates runs) and the Council (who receives the monthly invoice). The system’s job is: record which driver and vehicle were used on each run, and produce a monthly invoice for the Council.

A practical Level‑0 decomposition that covers the requirements is three main processes plus a few data stores:

  • Process 1: Allocate Runs — input from Manager, reads Routes/Drivers/Vehicles, outputs planned assignments.
  • Process 2: Record Actual Runs — records each run instance (RunID, date/time, routeID, driverID, vehicleID, morning/afternoon flag, any notes) into RunLog; this captures cases where morning/afternoon differ.
  • Process 3: Generate Monthly Invoice — reads RunLog (and rate/tariff data) and produces the invoice sent to Council; invoices are stored in InvoiceArchive.
    Data stores: Drivers, Vehicles, Routes, RunLog, InvoiceArchive. Keep the Level‑0 flows at a conceptual level (who gives what to the system, what the system stores, what it produces).

Example sketch (use this to guide your drawing):

[Manager] --> (1 Allocate Runs) --> [RunLog]
                     |                  ^
[Drivers DS] <-------+                  |
[Vehicles DS] <------------------------+
[Routes DS]  <-------------------------+

(2 Record Actual Runs) --> [RunLog]
(3 Generate Monthly Invoice) --reads--> [RunLog] --> [Invoice] --> [Council]

Notes and common pitfalls: don’t show field-level DB structure in Level‑0; keep transformations (processes) separate from stores. Follow ’s point: always map where each piece of data comes from and where it ends up. If you want a simpler starting point, draw a context diagram first (single process 0) and then decompose it into the three processes above.

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Member Avatar for aalqa

oky ,
you will find sloution just Go to this website and download Chpate 5 and read it
and then you will be able to solve your problem

best Regards

Member Avatar for griswolf

Level 0 is what amount of detail?
(What is the data?)
Where does the data start? (Who asks or tells?)
What stage(s) does the data go through on the way to the final sink/end?
What is the end result? (Who receives or stores?)

Member Avatar for aman007

Dataflow diagram simply show that how your data flow on project so when you make it remember all the process that From where data is coming and where it goes and how it processed.

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