Inserting two equal objects results in two facts, and each will trigger a matching rule. If your class Result contains a proper implementation of equals() and hashCode(), you may use KnowledgeBaseConfiguration conf = .... conf.setOption( AssertBehaviorOption.IDENTITY ); KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase( conf ); and then inserting another equal object will be ignored by the engine. You should not use not( exists(...) ) not() alone is the negated existence quantifier. Although not wrong, it's generally considered to be inelegant and confusing. -W 2010/11/8 J-C Walmetz <jc7442(a)yahoo.fr&gt;

My technical id is a long. But if I just do an equals id does not chage the issue. -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Same-rules-applies-tw... Sent from the Drools - User mailing list archive at Nabble.com.

Hello, I made a small test class result package com.sample; public class Result { private long resultId; public long getResultId() { return resultId; } public void setResultId(long resultId) { this.resultId = resultId; } public Result(long resultId) { super(); this.resultId = resultId; } } class test package com.sample; public class Test { private Result result; public Result getResult() { return result; } public void setResult(Result result) { this.result = result; } } Rule file package com.sample import com.sample.Result; import com.sample.Test; rule "Reload test" salience 10000 when $result: Result( $resultId:resultId) not (exists Test(result.resultId ==$result.resultId)) then Test test = new Test(); test.setResult($result); insert(test); System.out.println("rule started for id ="+$resultId); end Main program public static final void main(String[] args) { try { // load up the knowledge base KnowledgeBase kbase = readKnowledgeBase(); StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger(ksession, "test"); // go ! Result r1 = new Result(1); Result r2 = new Result(2); ksession.insert(r1); ksession.insert(r2); ksession.fireAllRules(); logger.close(); System.out.println(); } catch (Throwable t) { t.printStackTrace(); } } and the log you get rule started for id =2 rule started for id =1 so for each Result you put, it creates a test and the rules applies on,which is normal Does it help ? Regards Nicolas 2010/11/8 jc7442 <jc7442(a)yahoo.fr&gt;