Decision tables are an old design techniques, popular with business analysts since the 60s. Automated translation into code is what makes this approach so valuable, from a representation of tables as a spreadsheet, or in some other way. But consider (what is not an exhaustive analysis):
- If you do not have automatic translation into rules, decision tables are a good means for specifying requirements. But this does not mean that manually mimicking a translator is a good implementation technique. - Implementing a spreadsheet-to-rule translator is not too difficult, provided you know your target language very well. (But read on.) - On principle, decision tables restrict the rule language to a selective and parameterized conjunctive combination of patterns and constraints. (Table rows (or columns) is linear, condition grammar is recursive.) - One decision table must result in a number of structurally similar rules. To fully exploit the power of a production system such as Jess, you'll need more than one table or additional hand-written rules. - Apparently, the spreadsheet as a file defining constants for constraints mitigates the issue of hard coded constants, but it doesn't really solve it. For one thing, you cannot use (additional) rules for their validation, as you mght do with a set of "constant facts". Decision tables are just one technique among several for hiding or cushioning the intricacies of a rule language from greenhorn rule authors. But, at the bottom of it, designing and writing rules is a (sometimes taxing) work for programmers with experience, and no matter what the sales spiel of some rule vendor says: it's only simple things that really are simple. -W On 10 January 2011 04:04, <debasish.da...@cognizant.com> wrote: > > Now, we know how to do it using JESS, and concern is with other available > rule engine vendors - how they are managing this situation, since this is > pretty much common issue in most of IT-service industry projects using > rule-engine for some business decision; and as of today, vendors are > suggesting to use Decision Table concept to handle this homogeneous type > rules. To my understanding, this is nothing but the representing of 'n' > number of homogeneous type rules with different hard-coded constant values. > > Please make my understanding correct. > > > Regards > > DEBASISH DALUI (122816) > ---------------------------------------------- > Cognizant Technology Solutions US Corp > Cell : +1-216-835-2902 > >
