[Year 12 SofDev] DFD question

[Mark]

Hi all. It's an interesting situation.  This is my take on it.

We all probably start by seeing it from a human point of view: the customer
is dealing with the waiter, who deals with the system. So the customer is
an integral part of the transaction and therefore appear in a DFD or UCD...

But the waiter is not a part of the system: he/she interacts with it as an
external entity (EE).
So where does the customer fit in?  An EE to the EE waiter?  An EE once
removed? We don't do that in DFD or UCD.
>From the system's point of view, the waiter is an EE. The customer is a
fictional character that the system does not see, hear, or believe in. Only
the waiter exists to the system.  Everyone else is Santa Claus.

We could complicate it further and imagine that a child is giving her meal
choice to her mother who gives it to the waiter... should the child be in
the DFD/UCD now as an EE twice removed?
If a waiter were ordering his own lunch from the kitchen, would he be
represented again in the diagram - this time as a customerless EE?

As I read it, the customer is not directly interacting with the system; the
waiter is.  So the waiter appears as an EE.
So I would not include the customer at all in a DFD or UCD.

Anyone out there who did DFD/UCD at uni?

Cheers
Mark

On 25 February 2013 08:57, Kent Beveridge <kbeveridge at stbc.vic.edu.au>wrote:

>  Data flow to my understanding here..
>
> Waiter to Customer ....Request for order
>
> Customer to Waiter ....Food/Beverage order
>
> Waiter and Customer both 'entities' send data back to the central part of
> the 'system' (restuarant system) via the waiter
>
>
>
> Yep actors are waiter and customer.
>
>
>
> I havent started UCD stuff with my guys just yet..focussing on DFD's
> ...ucd next.
>
>
>  *Kent Beveridge*
> ICT Coordinator & Maths Teacher
> kbeveridge at stbc.vic.edu.au
>
>   ------------------------------
> *From:* sofdev-bounces at edulists.com.au [sofdev-bounces at edulists.com.au]
> on behalf of Mark [mark at vceit.com]
> *Sent:* Saturday, 23 February 2013 7:15 AM
> *To:* Year 12 Software Development Teachers' Mailing List
> *Subject:* Re: [Year 12 SofDev] DFD question
>
>   I had the same issue with the DFD and UCD for one of the programming
> outcomes.
> The restaurant customer would be an obvious actor/external entity in a
> system that takes meal orders.
> However since the waiter is the one interacting with the system, and the
> customer is interacting with the waiter, the customer does not appear at
> all in the system representation.
>
>  Sometimes what seems logical is not as it first appears.
>
>
> On 22 February 2013 13:14, Simone Tynan <Simone.Tynan at shcy.vic.edu.au>wrote:
>
>> Hi all,
>>
>>  I am having trouble with aspects of a DFD.
>>
>>  I have a DFD and context diagram in which shows a customer orders a
>> service and it is quoted and carried out.
>>
>>  Similar scenario, except the service is being carried out for a
>> beneficiary. (Think Ninja and assassins. ;-) )
>>
>>  The Customer is providing all details and payments. The beneficiary is
>> not actually adding to or receiving from the system (that I can see).
>>
>>  Are they still added as an external entity? Is there any connection
>> between them and the system?
>>
>>  Many thanks for any input/
>> Simone
>>
>> ************************************
>> Simone Tynan
>> eLearning Leader
>> LOTE Leader P-12
>> Simone.Tynan at shcy.vic.edu.au
>>
>>
>>    --
> --
> Mark Kelly
> mark AT vceit DOT com
> http://vceit.com
>
>
>     *St. Brigid's College *
>
> 97 Robinson Street, Horsham VIC 3400
>
> T 03 5382 3545   F 03 5382 0757
>
> ABN 72 749 438 155
>
> www.stbc.vic.edu.au
>
>
-- 
--
Mark Kelly
mark AT vceit DOT com
http://vceit.com
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