Background : I have an object model is as follows : Units 1 ---------------> 0..N Options where a unit (basically an item in stock), can have 0 … N Options. Items themselves have 2 primary fields - an item type (called group - a 3 digit number that represents the category the item belongs to) and a minor item number (called style - another 3 digit number that represents the styling of the item). Options represent additional enhancements that can be added to the base units. Very similar to options that can be purchased when buying a new car - wider wheels/tires, navigation system, leather seats etc. Now the use case is to provide the business with easy to use decision tables that will enable them to Price items based on the base unit and the options added to the base unit. The way pricing works is that each options has a standard price. However there are times when options associated with a specific group and style are priced differently. e.g. Option 'F103' would alway be priced at 100 bucks, however when added to a unit with group '010' and style '315' it should be priced at 120. I've created the following approach to meet the pricing rules above: 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" ) 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-res... Sent from the Drools - User mailing list archive at Nabble.com.