uml use case scenario needed

Question

Hello everyone,

Does anyone know where to get sort off a basic use case scenario for an auction site or a site like this one.

my site has to be more off an auction site then a q and answer site.

Basicly, from my ~limited~ understanding, when you start a project, you start with usecases and from there you are going to determine/build an objectmodel.

I would like to hear from someone, that has already got some higher level experience. I would like to see some examples, but advice is ok, also. Maybe, someone can provide some usefull links?

Starting from scratch is ok, but since there are already so many sites alike outthere

Thanks, Richard

Answer 1

It sounds to me as if you don't have any experience of UML at all.

UML at its simplest is a graphical means of describing a system, much the same as you may scribble something on a piece of paper or white board in order to show someone an idea or knowledge that you have.

As such there are very few hard and fast rules as to precisely what must be in any given diagram.

Most importantly diagrams should be meaningful and easily understood by those looking at them.

I doubt that you'll find any predrawn UML for the system that you're after.

Use cases just describe how you interact with a system or part thereof and how it interacts with everything else.

You should have one diagram for each use case e.g. User login use case; bid process etc.

Have a look here and here they may be of help to you.

Answer 2

In my opinion, use cases are one possible way to get a clear understanding of your requirements. So, as ChrisBD already stated, there won't be a diagram out there that suites your needs and, most importantly, even if it were, this is not desirable.

It's important to know that the valuable part of creating use cases is not the creation of a UML diagram(altough they are helpful for getting an overview of a system). The much more valuable process is writing the textual description of a use case.

There are various templates which guide you through the process (e.g., by Alistair Cockburn [1] or others [2,3] ). If you are interested in the subject, I can recommed the book "Writing Effective Use Cases"[4] by Cockburn.

[1] http://alistair.cockburn.us/Basic+use+case+template (great resources for use case in general)

[2] http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.23.255 (easy for starters)

[3] http://hcid.soi.city.ac.uk/research/Rescue.html (uc embedded in requirements engineering)

[4] http://www.amazon.com/Writing-Effective-Cases-Alistair-Cockburn/dp/0201702258/ref=sr_1_1?s=gateway&ie=UTF8&qid=1285833847&sr=8-1

Answer 3

Thank you Markus, I have problably seen, read all the links you provided above. I already wrote the use-cases.

The real challenge is to get an overall picture on how the system should work.

The flow, the database design and how to separate the bussiness logic so that changes can be made more eassaley. What language to use and what kind off framework in regards to speed, scalability, etc.

I need to have a somewhat broad understanding off it all, sothat I can go to some webdeveloper well prepared and not get into a situation where the developer is faced with the same questions, but does it on my time. I already had contact with one, and it sounded like he was going to have major coping problems. And then you hear, well sir, this is going to run in the papers. That does not sound very convincing.

I try'd reverse engineer a website but it only get's you sofar. Should this be a very hard case?

-> You can auction your items, and you can get biddings, but there it stops. I mean that there is no auctioneer in the system that is telling who has won. It does not go that far. It just has to manage the information. Connect the seller info to the buyer info.

I have been fishing around on what is out there what I can use to get a better understanding and especcially to keep the startingcosts low.

Anyone, who has any input, suggestions, please make a comment.