[Year 12 SofDev] Use case diagrams, data flow diagrams and context diagrams

[Esther Andrews]

Hi,
I don't recall a discussion about it, but I didn't teach it last year.
My 10c worth:

Re whether UCS is Analysis / Design... If a UCD is part of an SRS it must be being used as a design tool as it is specifying the requirements of a system.

Re the exam question
When investigating an existing information problem, a use case diagram is developed.
At which stage of the problem-solving methodology does this occur?
The reference to use case diagram here is a red herring. The key here is that the existing information problem is being investigated so it must be the analysis phase.




From: sofdev-bounces at edulists.com.au [mailto:sofdev-bounces at edulists.com.au] On Behalf Of Langham, Peter P
Sent: Friday, 11 October 2013 11:37 AM
To: Year 12 Software Development Teachers' Mailing List
Subject: [Year 12 SofDev] Use case diagrams, data flow diagrams and context diagrams

Good morning all,

A follow up to the email I sent out Wednesday morning, in which I asked the question about which stage in the PSM do UCDs, DFDs and CDs fit.

I've just been going over the 2012 VCAA Exam with my class in which Section A Question 1 asks:

When investigating an existing information problem, a use case diagram is developed.
At which stage of the problem-solving methodology does this occur?

A.      Design

B.      Analysis

C.      Evaluation

D.      Development

And the snippet from the Study Design that has me concerned:

Analysis involves:

* Determining the solution requirements. What information does the solution have to provide? What data is needed to produce the information? What functions does the solution have to provide? These requirements can be classified as being functional, namely what the solution is required to do, and non-functional, which describes the attributes the solution should possess, such as userfriendliness, reliability, portability, robustness, maintainability. Tools to assist in determining the solution requirements include context diagrams, data flow diagrams and use cases.

<snip>

Design involves:

* Planning how the solution will function, and the appearance of the resulting information. The solution design typically involves identifying what specific data is required and how the data will be named, structured, validated and manipulated. Typical design tools for this purpose include data dictionaries and data structure diagrams, input-process-output (IPO) charts, flowcharts, pseudocode, object descriptions. Solution design also involves, where appropriate, showing how the various components of a solution relate to one another, for example web pages, style sheets, scripts; queries, forms, reports; modules, procedures, functions. Typical design tools used to show relationships include storyboards, site maps, entity-relationship diagrams, data flow diagrams, structure charts, hierarchy charts, context diagrams, use cases. Planning the solution also involves determining the appearance of information generated from a solution. This typically involves identifying the position of text, images and graphics, font sizes, colours and text enhancements. Design tools used for this purpose include layout diagrams, annotated diagrams/mocks up.
I guess with the 2012 Section A, Question 1 you could argue that, the answer is B. Analysis due to the first line stating "..investigating an existing information problem.." indicates that is must be a use case diagram in the Analysis section of the PSM.

Do we need to teach students that if the question was instead "When planning a solution to an existing information problem, a use case diagram is developed." that the answer should have been A. Design.

It could become rather confusing if there was a short answer question about any of context diagrams, data flow diagrams and use case diagrams in the 2013 exam so I want my students prepared for all possibilities.

Was there a discussion about this question last year?

Thanks,

Peter Langham,
Narre Warren South P-12 College

From: sofdev-bounces at edulists.com.au<mailto:sofdev-bounces at edulists.com.au> [mailto:sofdev-bounces at edulists.com.au] On Behalf Of Mark
Sent: Wednesday, 9 October 2013 11:39 AM
To: Year 12 Software Development Teachers' Mailing List
Subject: Re: [Year 12 SofDev] (no subject)

It is an interesting point because there are logical design tools (e.g. UCD, context diagram) which are used during analysis to plan the requirements of a solution.
Then there are physical design tools which are used during design to plan the mechanics of a solution - e.g. IPO, pseudocode.

I'd only ever used DFDs as logical design tools, so it's interesting that Kevork (and Wikipedia) say that DFDs can be used in analysis and design.  Further research (e.g. http://www.ask.com/question/difference-between-logical-and-physical-dfd) says there are both logical and physical DFDs.

Old dog:  one new trick.

Cheers
Mark

On 9 October 2013 11:07, Kevork KROZIAN <kkrozian at ringwoodsc.vic.edu.au<mailto:kkrozian at ringwoodsc.vic.edu.au>> wrote:
Hi Peter,

Yes, you make a good point. UCDs are in analysis only. However Context and Data Flow diagrams are found in both analysis and design.

Kind Regards

Kevork Krozian
IT Pathways Manager
Ringwood Trade Training Facility
Tel: 0419 356 034

From: sofdev-bounces at edulists.com.au<mailto:sofdev-bounces at edulists.com.au> [mailto:sofdev-bounces at edulists.com.au<mailto:sofdev-bounces at edulists.com.au>] On Behalf Of Langham, Peter P
Sent: Wednesday, 9 October 2013 8:49 AM
To: Year 12 Software Development Teachers' Mailing List
Subject: [Year 12 SofDev] (no subject)


Good morning,



First year SD teacher - so my apologies if this has been discussed and resolved in the past.



I've noticed that Context Diagrams, Data Flow Diagrams and Use Case Diagrams are all mentioned in both the Analysis and Design sections of the PSM, page 17 in the study design.



Analysis involves:

* Determining the solution requirements. What information does the solution have to provide? What data is needed to produce the information? What functions does the solution have to provide? These requirements can be classified as being functional, namely what the solution is required to do, and non-functional, which describes the attributes the solution should possess, such as userfriendliness, reliability, portability, robustness, maintainability. Tools to assist in determining the solution requirements include context diagrams, data flow diagrams and use cases.

<snip>

Design involves:

* Planning how the solution will function, and the appearance of the resulting information. The solution design typically involves identifying what specific data is required and how the data will be named, structured, validated and manipulated. Typical design tools for this purpose include data dictionaries and data structure diagrams, input-process-output (IPO) charts, flowcharts, pseudocode, object descriptions. Solution design also involves, where appropriate, showing how the various components of a solution relate to one another, for example web pages, style sheets, scripts; queries, forms, reports; modules, procedures, functions. Typical design tools used to show relationships include storyboards, site maps, entity-relationship diagrams, data flow diagrams, structure charts, hierarchy charts, context diagrams, use cases. Planning the solution also involves determining the appearance of information generated from a solution. This typically involves identifying the position of text, images and graphics, font sizes, colours and text enhancements. Design tools used for this purpose include layout diagrams, annotated diagrams/mocks up.

It's my understanding that context diagrams, data flow diagrams and use cases should only appear in the analysis stage of the PSM.

Is this correct?

Thanks,

Peter Langham
Narre Warren South P-12 College


--
Mark Kelly
mark AT vceit DOT com
http://vceit.com

Day 19, I have successfully conditioned my master to smile and write in his book every time I drool.- Pavlov's Dog


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