Yes, much the same as you would with a RDBMS.

You'll have to insert the individual Lists (either by inserting their members, or by using "from").

Outer product:-

when
    FactA( )
    FactB( )
then

Inner join:-

when
    FactA( $pk : pk)
    FactB( fk == $pk )
then

left and right joins follow similarly (you'd have to check if the outer key equals or is null).


On 13 June 2012 13:04, soumya_sd <soumya_sd@yahoo.com> wrote:
Is it possible to have a rule that creates something similar to a SQL join.

For example, the working memory has the following:

List<Fact_A> and List<Fact_B>.

In the "if" of the drl rule we want to check

if Fact_A.someAttribute (some_condition) Fact_B.someOtherAttribute
//some_condition could be .equals(), .startsWith(), notEquals() ...

then
 //somehow Fact_A and Fact_B

Any examples or pointers would be greatly appreciated.

Thanks.


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