[rules-users] Getting different results from decision tables based on number of facts - all other fact information staying the same.

[Wolfgang Laun]

Today, on this list, I posted a way of getting the DRL from a decision
table. We should see the rules that are generated for the 2nd rule table.

And see below...


On 10 February 2011 18:11, groovenarula <gnarula1 at la-z-boy.com> wrote:

>
> rule "Set F103 Option price based on Group/Style"
>        salience 50
>        when
>                $unit : Unit (  group == "010", style == "315" )
>                $option : Option (unit == $unit )
>                          Option (optionPrice == null, code == "F103" )
>

This doesn't look right. I'd expect

   $option : Option (unit == $unit, optionPrice == null, code == "F103" )

-W



>        then
>
>            $option.setOptionPrice(120.00);
>            retract ( $option );
> end
>
> rule "Set F103 Option base price"
>        salience 5
>        when
>                $option : Option ( optionPrice == null, code == "F103" )
>        then
>                $option.setOptionPrice(100.00);
>                retract ( $option );
> end
>
> Question : Is there a better way to implement the rules stated above ?
>
> The DRL works as expected when I insert one or multiple items in working
> memory. The appropriate rules fire and when Group / Style = 010 / 315, the
> price for the option is set to 120, but when Group and Style is anything
> else, the option does get priced at 100.00.
>
> However, when I try to implement the same rule using decision tables, I get
> different results. To implement the above, I created 2 rule tables :
>
> 1. The first rule table establishes the pricing of options that are not
> specific to a group / style as follows:
>
> CONDITION                                                  PRIORITY
> ACTION
> $option : Option
> code == "$param", optionPrice == null               5
> $option.setOptionPrice($param); retract($option)
>
> 2. A second rule table that adds the unit constraints as follows (with
> PRIORITY 50):
>
> CONDITION              CONDITION              CONDITION
> $unit : Unit                                              $option : Option
> group == "$param"  style == "$param"     unit == $unit, code == "$param",
> optionPrice == null
>
> ACTION
> $option.setOptionPrice($param); retract ( $option);
>
> There in lies my dilemma.
>
> When I send one unit with Group Style 010 315 and option F103, it prices
> the
> option properly @ 120.00.
>
> When I send in a unit with a different style (same group = 010), it also
> prices the option properly at 100.
>
> When I when I send 2 units together - one with group and style 010 315 and
> another having the same group but a different style (515 for example), it
> prices the option for both units @ 120 :
>
>   010 315 option price = 120.00 (correct result)
>   010 515 option price = 120.00 (wrong result)
>
> But if the second unit on the 2 units has a different group (011 for
> example), I get the right option prices :
>  010 315 option price = 120.00 (correct result)
>  011 315 option price = 100.00 (correct result)
>
> For what ever reason, it does not fire the generic pricing option even
> though the second unit's G/S does not match 010 315.
>
> Can anyone please shed some light on what I'm doing wrong here ?
>
> Any help will be appreciated.
>
> Thanks in advance.
> Gurvinder
>
> --
> View this message in context:
> http://drools-java-rules-engine.46999.n3.nabble.com/Getting-different-results-from-decision-tables-based-on-number-of-facts-all-other-fact-information-s-tp2467364p2467364.html
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>
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