[rules-dev] Firing rules only if action causes updates to data?

[Michael Neale]

yeah that is the difference between propositional logic and first order? (I
think I have my terms correct, or is it predicate vs. first order? I can not
be sure).

IN any case, when you hear people talk about "first order" logic, normally
that means the higher level Conditional Elements like not, exist, and soon,
forall, accumulate, collect etc.

On 2/28/07, Peter Lin <woolfel at gmail.com> wrote:
>
>
> simple
>
> rule x:
>
> if
>   a = 5
>   b = 3
>   c != 0
> then
>   c = 0
>
> keep in mind that using negation NOT means that condition does not exist.
> In other words, if I have this rule
>
> rule y:
> if
>   a = 5
>   b = 3
>   not c = 0
> then
>   c = 0
>
> rule y means a is 5, b is 3 and no c is zero.  Say i assert 100 objects to
> the working memory and 1 of them has c = 0. it means rule y would never
> fire, since there is a fact that satisfies "not c = 0".
>
> hope that helps
>
> peter
>
> On 2/27/07, Premkumar Stephen <prem18 at gmail.com> wrote:
>
> > Hi Dev team,
> >
> > Its been fascinating to watch the growth of this tool. Here is my
> > question:
> >
> > Rule x:
> > if
> >    a = 5
> >    b = 3
> > then
> >    c = 0
> >
> > Now, I have written this rule to run when a = 5 and b =3. But actually,
> > I would like it to ideally run when a = 5 and b = 3 and c != 0
> >
> > Now, does the second scenario lead to any savings. In Ilog, the second
> > scenario will result in the rule NOT being added to the agenda whereas it
> > would in the first.
> >
> > I cannot code the second scenario into the rule as the rule ( as seen in
> > UI) needs to match the requirements version ( in Doors) and they do not want
> > to add these to the requirements. I would just like to make the second
> > version for performance. We have noticed that less number of rules would
> > fire.
> >
> > Now, if a = 5, b = 3 and c = 0, is there a way Drools can look at it and
> > say, let me not fire this rule since there is no practical use anyways.
> > If not, what are the ways to automate not firing rules in scenarios
> > where action does NOT cause updates to data.
> >
> > Thanks!!
> >
> > _______________________________________________
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> > rules-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/rules-dev
> >
> >
>
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