org.eigenbase.rel.jdbc
Class AddFilterToQueryRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      org.eigenbase.rel.jdbc.AddFilterToQueryRule

 class AddFilterToQueryRule
extends RelOptRule

AddFilterToQueryRule grafts a FilterRel onto a JdbcQuery.

This rule only works if the query's select clause is "*". If you start with a FilterRel on a ProjectRel on a TableAccessRel, this will not be the case. You can fix it by pushing the filter through the project. (todo: Implement a rule to do this.)

Since:

Nov 26, 2003

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/jdbc/AddFilterToQueryRule.java#13 $

Author:

jhyde

Field Summary

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

AddFilterToQueryRule()

Method Summary

void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

convert, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, mergeTraitsAndConvert, mergeTraitsAndConvert, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

AddFilterToQueryRule

AddFilterToQueryRule()

Method Detail

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. 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 RelOptRuleCall.transformTo(org.eigenbase.rel.RelNode) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)