net.sf.saffron.rel
Class RemoveDistinctRule

java.lang.Object
  |
  +--net.sf.saffron.opt.VolcanoRule
        |
        +--net.sf.saffron.rel.RemoveDistinctRule

public class RemoveDistinctRule

extends VolcanoRule

Rule to remove a DistinctRel if the underlying relational expression is already distinct.

Field Summary

Fields inherited from class net.sf.saffron.opt.VolcanoRule

description, planner

Constructor Summary

RemoveDistinctRule()

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

RemoveDistinctRule

public RemoveDistinctRule()

Method Detail

onMatch

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