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Home » Discussions » Best Practices

expression rule vs decision

krisk

Hi,

     I know decision designer is new feature.

     Would like to check what are best use cases for writing expression rules  and  best use cases write decision rules? 

     Where are these decision rules are going to stored. Do we have access these tables         

      Can we group decision rules under one rule set and make use of them in another rule?  Can we use this decision designer as a typical rule engine(IBM ODM,DROOLS,PEGA rule engine) functionality?

Thanks.

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  • 0
    Certified Lead Developer
    Decisions sound like a good idea on paper, and I'm sure there are a ton of real-world use cases, but every time I've sat down to implement something using a decision, i've ended up having to bail out and do it in a traditional expression rule, either because decisions aren't expressionable, or just plain not flexible enough. I'd love to hear how others have gotten around this, becuase maybe I've been missing out.
  • 0
    Certified Lead Developer
     in reply to Mike Schmitt
    I agree with Mike.
    I recommend / use decision tables when they are 'clear cut' and replace a 'simple nested if'. When I need to do more complex things (need things to be expression-able, I use expression rules.

    Decision Tables are a step to give more power to the 'Citizen Developer'. So, in workshops with the business, they are great. In actual implementation, I use them where very straight forward.
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  • 0
    A Score Level 1
     in reply to ChristineLHutchison
    Just to add to this - worth considering that decision tables give zero audit history for decisions other than the version history, so if knowing what the settings were in the past is important, decision tables may not suit. That said, it's possible to use something like from/to (implementation) dates so that a setting is used depending on the date that is passed in, but this may not suit all implementations.
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