Re: [rules-users] forall with nested collections
The hierarchical data model is rather unwieldy.
A relational model would have the following entities:
Person( personId,... )
Vehicle( vehicleId, make,... )
Ownership( personId, vehicleId, year )
and it would be quite easy to handle such questions:
Person( $pid: persondId)
Ownership( personId == $pid, $vid1: vehicleId )
Vechicle( vehicleId == $vid1. $make1: make )
not ( Ownership( personId == $pid, $vid2: vehicleId != $vid1 )
and
Vehicle( vehicleId == $vid2, make != $make1 ) )
That said, here's some code to do it in Drools:
$result: PersonData( $id: identifierCode )
Set( count == 1 )
from accumulate( $vd: VehicleData( ownerIdentifierCode ==
$result.identifierCode )
init( Set ms = new HashSet() ),
action( forall( VehicleYearData vyd: $vd.getData() ){
forall( VehicleEntity ve: vyd.getVehicleEntity() ){
ms.add( ve.getMake() );
}
} ),
result( ms ) )
The rule should fire if that person owns cars of just one make; use >1
for the opposite condition.
Untested!
-W
On 14/05/2014, braveheart85 <andrea.pacifico.85(a)gmail.com> wrote:
Hello,
I'm pretty new to Drools hence i apologize if my question is newbie but i'm
getting crazy.
I'm trying to write a functioning query since yesterday without fortune.
I have data about vehicles owned by person organized for year. My structure
is:
VechicleData
|___VehicleYearData
|____Vehicle
I have inserted in Drools only the root of the hierarchy (VehicleData)
because insert all objects has been problematic for me. Now i need to check
if a person has all vehicle of the same make.
I have tried this:
$result: PersonData( $id: identifierCode )
forall
(
($o: VehicleData( ownerIdentifierCode == $result.identifierCode )) &&
($y: VehicleYearData( ) from $o.data) &&
($v: VehicleEntity( ) from $y.vehicleEntity)
)
VehicleEntity( this == $v, make == "BMW" )
)
and this:
PersonData( $id: identifierCode )
$list: List( ) from accumulate (
(and
$o: VehicleData( ownerIdentifierCode == $id )
$y: VehicleYearData( ) from $o.data
$e: VehicleEntity( ) from $y.vehicleEntity
),
collectList( $e )
)
forall (
$v: VehicleEntity( ) from $list
VehicleEntity( this == $v, make == "BMW" )
)
and many other...
Someone can help me??
Thank you.
Andrea
--
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