I need some examples of Use Case, Data Flow and Entity-relationship model diagrams. Any website, tutorial or even an eBook on the subject is welcomed.

I need examples, not text. I have the text in a book and SD, but the examples are poor and not very usefull.

Thank you.

Agile Modeling is a favorite of mine for USE Case Diagrams

often times you can find good examples on college websites, here's one for an [url=http://www.infocom.cqu.edu.au/Courses/spr2000/95169/Extra_Examples/ERD.htm]
ERD[/url] that I think is good

This post has been edited by skyhawk133: 15 Nov, 2007 - 09:54 AM

Thanks, fyrestorm. That's an useful source.

I'll need some more on Data Flow.

This should get you going on the Data Flow Diagrams

Thanks again.

Now, I wanna ask you something. I need these for my SD exam next week. How much do you need the diagrams in practice?

I cover DFDs on my blog as well, providing some example graphics. So be sure to take a look (link below)

Martyr2's Programming Underground - The Mysteries of Data Flow Diagrams

As for their use in real life, it depends on what you do. As a software developer I don't find many companies that use them unless they are really building a complicated system with a lot of moving parts. You can find them a lot in the database design world where I have used them to layout how databases move around data to various applications and such. Engineers use them for building complex systems and even their circuitry type of charts can be compared to DFDs in some aspects.

But as a programmer I haven't found them used extensively, but you should know what they are so that when presented with one from a system designed long ago (and you are expected to update) it can help get you on the ground and running.

I find Data Flow Diagrams are usually the easiest to understand, ERDs are a bit more complex because you have to make sure you identify all the objects of a problem and their relationships to one another.

Hope that answers your question.

I'd tend to agree with Martyr2. Been quite a while since I've worked in a smaller dev shop, but i can tell you that DFDs are used very extensively when designing and implementing a large scale application or architecture. My teams are require to produce them for any project.

One resource that I found helpful as an introduction to modeling was this UML tutorial:

http://dn.codegear.com/article/31863

It's a little sparse, but much clearer and more tutorial than most that I've looked at.

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