[rules-users] Basic rules question

Hi I am a newbie to rule based applications and trying to get the concept of rules. I have couple of questions about rules to start with, not specifically about Drools though. Q1 - Should rules be data/model specific or can/should they be generic or both ========================================================== e.g. If selected product "TYPE" is "laptop", then category "RAM" should have all "DDR" type items compatible ( selecting items matching certain property ) OR If selected product is "IBM T42", then category "RAM" should have "512MB DDR" , "1024MB DDR", "2048MB DDR" compatible. ( assigning individual items in rules ) OR Combination of both Q2 - How should be the data modeled in above case ========================================================== e.g. in product master, each item ( e.g. T40, T42 ) should have a "TYPE" ( e.g. desktop or laptop ) , all items in category "RAM" should have a "TYPE" ( e.g. DDR ) and then control the assignment of RAM options to the PRODUCT through Rule using "DDR" type ? OR in product master, each item ( e.g. T40, T42 ) should have a "TYPE" ( e.g. desktop or laptop ) , all items in category "RAM" should have a "compatibleProduct" column ( e.g. desktop or laptop ) and control the assignment of RAM to PRODUCT through "dynamic" rules by selecting all the RAMs by passing the "TYPE" of the product to the database handler. Am I making my point clear ? Thanks Abhay