Author Topic: Activity vs Sequence Diagram at the BA level  (Read 2380 times)

jeshaw2

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Activity vs Sequence Diagram at the BA level
« on: March 12, 2006, 06:34:45 pm »
I'm reviewing a UML textbook aimed at the Business/Requirements Analyst.  The author recommends the Activity Diagram over the Sequence Diagram on the basis that the Sequence Diagram is too complicated for users & stakeholders to understand.

What is your experience and practice?
Verbal Use Cases aren't worth the paper they are written upon.

thomaskilian

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Re: Activity vs Sequence Diagram at the BA level
« Reply #1 on: March 12, 2006, 11:03:07 pm »
My opinion: There is a 1:1 transformation between both diagrams, so they show the same semantic. The way SDs present information looks more technical (matrix oriented) than ADs. As ADs look more arty it's probably more liked by non-technical people and generates thus less opposition.

mikewhit

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Re: Activity vs Sequence Diagram at the BA level
« Reply #2 on: March 13, 2006, 05:15:33 am »
The SDs focus on cause and effect; temporal/sequential (!) relationships. The ADs are more 'procedural' - what gets done, what gets done next.

Depends on what's important - IMHO.

Kevin Brennan

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Re: Activity vs Sequence Diagram at the BA level
« Reply #3 on: March 13, 2006, 08:34:38 am »
I personally use both.

However, the feedback we've been getting on the BoK is that a pretty significant percentage of BAs find the sequence diagram to be too technical, while everyone's OK with the activity diagram.
Sr. Consultant at blue sands Inc. and Vice President, Body of Knowledge at the IIBA. All opinions are my own.

GTM

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Re: Activity vs Sequence Diagram at the BA level
« Reply #4 on: March 13, 2006, 03:30:57 pm »
I'm also voting for ADs for your task. And as mikewhit said, there *are* differences between the two.
ADs can show parallel execution and related stuff. This is not possible to express in one SD - as the name tells you - it will show just one thread of many possible scenarios.
To show timing details, consider using the Timing Diagram, although they are a bit limited at the moment.


StefanPears

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Re: Activity vs Sequence Diagram at the BA level
« Reply #5 on: March 14, 2006, 12:33:00 am »
hi all!
after you have collected your use cases (and I hope you have only a small amount of them) it's a good idea to create some ADs in order to explain the desired business work flow to the business people and hopefully they will agree. Pls note that the objects in your ADs are only those that are needed for the object flows. Next step is to create business(!) sequence diagrams with lifelines of business classes (from business class models) with its business attributes and operations. These SDs are on the same level as the ADs before, probably describing the same business process, though there is (TMHO) no 1 to 1 transformation between them. The SDs and CLDs are useful for the communication with architects, developers and other IT specialists.
Stefan
« Last Edit: March 14, 2006, 12:34:42 am by sbirner »

jeshaw2

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Re: Activity vs Sequence Diagram at the BA level
« Reply #6 on: March 14, 2006, 03:05:53 am »
This is all good stuff!  

I'm setting up a time crunched workshop for BAs on modeling the dynamic aspects of their application systems and this stuff is a great help.  Since BAs communicate both with users and developers, it sounds like I should introduce them to both ADs (for use with users) and SDs (for use with developers).

Any additional thoughts on best practices with these diagrams?

Thanks a bunch folks,
Jim
Verbal Use Cases aren't worth the paper they are written upon.

Bruno.Cossi

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Re: Activity vs Sequence Diagram at the BA level
« Reply #7 on: March 15, 2006, 06:33:26 am »
Hi,

the way I see it, it all depends on the definition of BA. In the (typically larger) companies where there is a clean distinction between the Business Analyst and Systems Analyst, I typically see BAs creating Activity Diagrams, then the Systems Analysts taking the information from the BAs and translating them into the information required by the developers, which includes Sequence Diagrams.
I have found it difficult to have non-technical BAs creating sequence diagrams, but generally they had no issues with Activity Diagrams. Occasionally though I come across companies where the roles of BA and SA are intermixed and then there is no issue with SD.

Not sure if this helps!
Bruno
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Kevin Brennan

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Re: Activity vs Sequence Diagram at the BA level
« Reply #8 on: March 15, 2006, 05:15:28 pm »
If the BAs are involved with the Class Model then they should understand the SD. After all, sequence diagrams show how the classes interact to fulfill a use case scenario!

If they're not concerned with the classes or the domain model, then the AD is likely to be all they need or want. As Bruno suggests, it has a lot to do with their particular responsibilities.
« Last Edit: March 15, 2006, 05:19:59 pm by Kevin_Brennan »
Sr. Consultant at blue sands Inc. and Vice President, Body of Knowledge at the IIBA. All opinions are my own.