[Zope-CMF] Project-style workflows, DCWorkflow, SQL, etc.

[Vincenzo Di Somma]

I perfectly agree, IMO we have should not try to evaluate which one is
better but try to consider the possibility of supplying both to
developers, and let them choose which one fits his needs.


Phillip J. Eby wrote:

 > At 05:36 AM 10/13/01 +0000, Kent Polk wrote:
 >
 >> Shane Hathaway wrote:
 >>
 >> > - How do you implement subflows?  With DCWorkflow and the portal_types
 >> > tool, you can set up objects that get stored in workflowed containers.
 >> > The contained objects can have partially dependent workflows.
 >>
 >> This is (IMO) the big difference between entity based and activity
 >> based workflow. With activity based, you don't need to create some
 >> Item to have a workflow, and indeed, much workflow doesn't revolve
 >> around creating items, but mainly passing information around, often
 >> resulting at different points in creating both temporary as well
 >> as permanent informational items.
 >>
 >> Activity-based subworkflows are not (necessarily?) related to a
 >> created item, but to a request that someone or something is waiting
 >> on or for.
 >
 >
 > I'm not sure that this is really a meaningful distinction.  Why can't a
 > request *be* a created item?  It's going to be an object, no matter what
 > approach you take.  It might as well be a content object.
 >
 > I can't say that I'm an expert on workflow systems, but I've studied the
 > formal and informal metamodels of a lot of different systems (about a
 > dozen), both academic and commercial (including a lot of OMG/WFMC
 > stuff), and as far as I can tell they are all essentially isomorphic.
 > Some people prefer to use a Petri-net modelling approach where tokens
 > move like race cars around a flowchart, others prefer to view the state
 > machine as being contained within an object.  Some systems use special
 > restrictions on composition of flows in order to achieve certain desired
 > properties, such as provable termination, or the ability to specify most
 > things as a hierarchy of operations.  Some systems make distinctions
 > between tasks, assignments, and workflow instances, and others use fewer
 > distinctions and combine concepts.
 >
 > I have occasionally seen "entity-oriented" workflows that are tied to
 > work product and are not really generic workflow tools like DCWorkflow
 > is.  But as far as I can tell, DCWorkflow is "computationally complete"
 > where workflow is concerned.  The only thing it "lacks", if you can
 > really say that, is tools for managing inter-task communication and
 > synchronization.  However, this is not due to a lack of expressivity in
 > the model used by DCWorkflow.
 >
 >
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Vincenzo Di Somma - Responsabile Ricerca e Sviluppo - Icube S.r.l.
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