Re: [rules-users] Accessing properties of an object within a Nested Collection of a Nested Collection

Yes, the idea is to insert Models, Brands, Parts, and possibly additional facts. You might want to keep lists of child objects or used parts in the parent objects - see Michael's rule. Otherwise: Relating a Model to a Brand and a Brand to a Manufacturer is simple: a "parent" reference is sufficient. For Parts, you might want to establish a Gozinto fact, combining a Part and a Model. rule "whereIsPV999999" when $part: Part( partName == "PV999999" ) Gozinto( part == $part, $model: model ) Model( this == $model, $brand: brand ) Brand( this == $brand, $manu: manufacturer ) Manufacturer( this == $manu ) then System.out.println( "PV999999 used in " + $model + "/" + $brand + " by " + $manu ); end For deciding between using this or the "contains" search in potential parents, there are issues w.r.t. the number of objects you have, the rules you'd really use, and how frequently what is evaluated, and concerning the ease of rule maintenance. It is indeed possible to extract all from a small set of Manufacturer facts, but nested "from" CEs are most likely bad for performance. -W On 02/05/2012, James K <james_kosa(a)verizon.net&gt; wrote: