UCD Q: Difference between Basic Path & Simple?

[austin_hastings]

In a Use Case Diagram, EA offers scenario types of Basic Path, Alternate, and Simple.

In the Settings -> General Types -> Scenarios ... dialog box the descriptions are:

Simple -> Standard Scenario
"Used to describe ordinary usage."

Basic Path -> Basic Execution Path
"The standard execution path with no exceptions."

I'm afraid I don't get it. Can someone explain the difference between these two types? Is there some rule-of-thumb for when to choose one versus the other, or are they parts of different specializations of UCDs or what?

Thanks,

=Austin

[thomaskilian]

Search the net for Cockburn and/or Bittner on How To Write Use Cases. There's also a white paper on Sparx site you might want to read first.

[austin_hastings]

You may find it surprising, but my first stop was Google, and not the "site search" feature on SparxSystems.com.au. Nowhere have I found an explanation of the difference.

Frankly, I think there isn't one. I suspect that the "Simple" and "Basic Path" entries are redundant with each other, and probably left over from some sort of methodology/taxonomy battle from the early days of UML.

But still, they're both there, and they've been there for as long as I've subscribed to EA (a few years now). So I wondered.

And in fact, since "Try searching the net" didn't get me anyplace, I'm still wondering:

What's the difference?

=Austin

[KP]

I'm only guessing, but I'd say that if a use case has multiple paths then one is the "basic path" and the rest are "alternate", but if a use case doesn't have multiple paths then the one and only path is "simple".

[ronnie]

Use Cases seem to be the prime focus of debate in any UML discussion I have.
There are various differences of opinion between UML-centric people and what I call Cockburn-centric (see "Writing Effective Use Cases", 2001) Use Case writing.

I try to sit somewhere in the middle.

Apart from all this confusion EA now adds this 'simple' path - which I find doesn't fit anywhere. Firstly it is very rare that a use case will have only one path - that implies that it hasn't been investigated far enough - and even if it did, surely that would be the Primary (Basic) path still - that way when you finally work out later on that there is actually an exception to the rule (which there always is) you don't have to go back and change the simple to something else.

Personally I am not very enthusiastic about the scenario entry tab in EA - it doesn't give enough room or tools to help that much. It would be much nicer if each of the lines could be automatically numbered and had some indentation management for extensions.
I am rapidly coming to the opinion that it is better to shove another diagram and objects underneath the use case to cover the scenarios at present.

Ronnie