Context Diagram (1 Viewer)

[JJPH]

I wrote, "This is not in the syllabus" (hoping my memory served me right in the exam) and then i just drew one anyway.

Came home today, and did a search through the syllabus for "context diagram". And it's not there.

Someone correct me if i'm wrong here, but its in the IPT syllabus, but not the SDD one, right? Or................ terribly wrong?

 

[Xachro]

I'm pretty sure you have to do it in SDD, considering its in the excel text book page 44.

 

[hstanley]

ah...

isn't that one of the square circle square thing??

I drew a IPO chart
and then put the Inputs in a square then an arrow connecting it to the circle which had the processes and then an arrow to the square which had a square with the outputs.

i hope that was right.

 

[chucknthem]

didn't know what that was, so I drew a storyboard. :rofl:

 

[adgala]

dfd = level 1 context diagram
a context diagram is a simplified dfd

 

[JJPH]

Xachro: Well who to refer to, Excel or BOS?

adgala: Well that's stupid enough for BOS to not list it in the document? Or..? (cause i know some text books refer to a structure diagram as a chart or something, i forget)

 

[Xachro]

Context diagrams have a single process (in a circle) connecting external entities (in a box) through data flow (arrows). So the one I drew was
[User] -- Username, Password, Answers - > (System) -- Resource Usage Info --> [Hospital]
^--(from system to user)-- questions, diagnosis--

 

[Sober]

I think I drew a system flowchart, I had never heard of the term before.

 

[priesty]

Context diagrams have a single process (in a circle) connecting external entities (in a box) through data flow (arrows). So the one I drew was
[User] -- Username, Password, Answers - > (System) -- Resource Usage Info --> [Hospital]
^--(from system to user)-- questions, diagnosis--

lol... too much detail there mate.

in context diagram there is no need for the actual "data" being transfered to be specified (that's only in DFDs)

a context diagram is a simple dfd with entire processes being within a Circle.

I had the two external entities as well.. [User] and [Hospital] joined to the (Health System) in a circle, join them up and viola.... easy 2 marks.

Some people I know put in the Database (as if it were a DFD) but Context Diagram has no Database symbol.

 

[Xachro]

Oh really, you dont need data in a context diagram? We've always chucked it in there for IPT exams. Oh well, at least I shouldnt lose marks. Most of the stuff I did I put heaps of detail in, cause I felt I had alot of time. Example: I did all my algorithms twice, once a draft on the exam sheet where I messed with it, chucked in lines with arrows pointing to other places and was generally a mess, then did the real one in the booklet. Also helped to compare with others in the class when I finished the exam.

 

[priesty]

Oh really, you dont need data in a context diagram? We've always chucked it in there for IPT exams. Oh well, at least I shouldnt lose marks. Most of the stuff I did I put heaps of detail in, cause I felt I had alot of time. Example: I did all my algorithms twice, once a draft on the exam sheet where I messed with it, chucked in lines with arrows pointing to other places and was generally a mess, then did the real one in the booklet. Also helped to compare with others in the class when I finished the exam.

Yeh, NO DATA in context diagram.

Don't do it in IPT, u'll lose marks (I do both as well). Context is strictly a very abstract view of the entire system. Dataflow is where u are allowed to get more detailed and specifically mention the "Data Flow".... It's practically one of the essential differences!

 

[mattyz]

erm wm abusef we are tought to label what is going to and from the process you cant lose marks lol so dont say you can lose marks they only give lol

 

[drewgcn]

Priesty, I'm fairly sure you wouldn't lose marks for labelling a context diagram. I did IPT two years ago and SDD now, I always used to label them, but it isn't essential.

Though I think you can lose marks for not labelling a DFD.

 

[mattyz]

yer drew lol abusef has no clue what he is on about lol let him go

 

[priesty]

ok, sorry. i stand corrected.

idno, just my teacher has always drilled that into me (the whole "don't label context diagrams because the examiners will question whether u truly understand what it is")

"Though I think you can lose marks for not labelling a DFD." - Yeh, I agree with u there.... Or more, you wont get the marks if u don't label it.

Sorry for any confusion

 

[maskd]

I put User -> Web-based system -> User

 

[hotcocoa]

BOS does have it..

"Software Design and Development Stage 6..
Software and Course Specifications
High School Certificate 2001"

(might be old, but it is still the basis of what is introduced to us in the exam)

After the 'Foreword' is the 'Introduction'
On the first page of it, contains 'General Specifications'

"Representaional Tools
Context Diagrams
Context diagrams are used to represent entire information systems. The system is shown as a single process along with the input and outputs (external entities) to the system. The external entities are connected to the single process by data flow arrows.


The symbols used are:
(circle)'Process' a single process representing the entire system as a circle
(arrow) data flow representing the flow of data between the single process and external entities
(rectangle)'External entity' any person or organization that provides data to the system or recieves data from the system."


Thus I had 'user' -> 'hospital web system' (circle) -> 'hospital management/staff' and 'user' (rectangles)

 

[maskd]

Hmm are hospital management/staff even involved in this system, to me it seemed more like an expert system, as it makes a diagnosis off questions asked. I'm thinking something similar to http://www.20q.net/

EDIT: Read post by hotcocoa, so I guess I was wrong, hospital management/staff would be involved because they input the recommendations/diagnosis of various conditions. Ah well...

 

[hotcocoa]

well.. it does say "Information from the system will be used by the hospital to plan resource usage" so who else but the management and staff will need this?

 

[maskd]

Ah ... I did not read that ... Hopefully I may get 1 mark.