Class OJPlannerFactory.DistinctToExistsRule

Enclosing class:

public static class OJPlannerFactory.DistinctToExistsRule
extends VolcanoRule

Rule to translate a JavaDistinctRel into a JavaExistsRel, provided that the select list contains zero columns.

Field Summary
Fields inherited from class net.sf.saffron.opt.VolcanoRule
description, planner
Constructor Summary
Method Summary
 void onMatch(VolcanoRuleCall call)
          This method is called every time the rule matches.
Methods inherited from class net.sf.saffron.opt.VolcanoRule
convert, getOutConvention, toString
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail


public OJPlannerFactory.DistinctToExistsRule()
Method Detail


public void onMatch(VolcanoRuleCall call)
Description copied from class: VolcanoRule
This method is called every time the rule matches. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back VolcanoRuleCall.transformTo(net.sf.saffron.rel.SaffronRel) to register the expression.

Specified by:
onMatch in class VolcanoRule