Context Diagram - Inputs/Outputs

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May 19, 2009, 9:11:00 PM5/19/09
to Volere Requirements

I was wondering if I could get an opinion regarding the level of
detail we should put into a Context Diagram.

Perhaps the best way of explaining this is with an example.

The work is 'A person applying to be a member of our organisation'. We
are a health insurance company

One of the adjacent systems is a person (the other is the work).

The Business event is 'a person sends in the paperwork to apply to be
a member'

This paper work will contain a number of different documents (but not
necessarily all of them). These may include-

-An Application form
-Some medical information from their doctor or health professional
-Direct Debit forms for payment
-Legal documents

My question is do you represent these as several different flows
between the adjacent system or as one. i.e.



Suzanne Robertson

May 19, 2009, 10:39:25 PM5/19/09
Dear Jason,

Think of this as a piece of work that responds to one business event. The
business event is: Person Wants To Be A Member of Our Organisation

The input dataflow is everything that comes from the person when that event
takes place. I suggest that you call the input flow something like
Membership Application Details

Then you do a data dictionary definition

Membership Application Details = Application Form + Medical Information
+ Direct Debit Forms + Legal Documents.........

What are the output flows in response to this event? I envisage something

Accepted Membership
Refused Membership

Depending on whether the Membership Application Details conform with your
business rules for accepting a new member.

Hope this helps. Keep talking.

Suzanne Robertson
Suzanne Robertson
Principal of The Atlantic Systems Guild <> <>

Our new book "Adrenaline Junkies and Template Zombies - Understanding
Patterns of Project Behaviour" is the Jolt Award winner, Best General
Computing Book of 2008-2009.


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