# Data Flow Diagram critique



## Jarlaxle402 (Nov 23, 2010)

Greetings all,

I'm in a group project in a Systems Design and Development class, and we have a project that requires us to redesign a college parking lot system. I have been given the lovely task of doing the Logical Data Flow Diagram for the "new" system if it were to be implemented. However I've been having a tad of trouble trying to build it up. I've written several different (and some incomplete) narratives to this DFD, and drew one complete picture. I'm not asking for anyone to do my work, I'm just asking for a critique on how I could make mine better. I'm not really worried about the narratives, they are just to help you follow what I'm trying to accomplish.

Here are the few renditions:

1. Student goes to parking web site
2. Student enters student info into parking registration screen
3. Form data compared to applicable data to determine if they are eligible (outstanding fines, student status, etc.)
a. Yes  go to #4
b. No  You are not eligible
4. Student enters car data info into car registration screen
5. Check legality of car, plates and license
a. If checks our  go to #6
b. No  Not Eligible for Parking Pass
6. DPS is informed and student is prompted to retrieve parking sticker at DPS. Subtract 1 from available parking
7. Student receives parking pass

*2nd time making it*
Student inputs information into
1: Check student status
A. Student Info is clean, proceed to 2
B. Student Info is flagged, proceed to Denial.
2: Vehicle Status
Student puts in vehicle information into
[Police Database]
A: Vehicle is clean, proceed to 3
B: Vehicle is "dirty" or incorrect information, proceed to Denial
3: Acceptance of Parking Permit
A: Student is informed on how to obtain parking pass
B: Student and Vehicle info is sent to 4
4: Update DPS database

*3rd Time making it*
The Student(external entitity) inputs their details which is sent to "Validate Student Info" (Process). This process results
a: Student info is good -> prmopted to input car info
b: Student info is bad -> prompted to exit
c: Student info is incorrect -> prompted to retry
"Validate Student Info" sends Student info to "Parking Registration List" (data store)
The Student than puts their car info, which is sent to "Validate Car Info" which sends the information to Police Database (external database). This process results in
a: Car comes out clean -> Tells "Validate Car Info" to continue
b: car comes back as dirty -> Tells Validate care info to stop progression
c: Incorrect car info -> Tells Validate car info to tell student incorrect car info
"Validate Car Info" sends car info to "Parking Registration List"(data store) connected to student info.
[Incomplete after this]

I appreciate and welcome any comments. I've been at this for a bit, and it has been a tad frustrating.


----------

