org.eigenbase.rex
Class RexCorrelVariable

java.lang.Object
  org.eigenbase.rex.RexNode
      org.eigenbase.rex.RexVariable
          org.eigenbase.rex.RexCorrelVariable

public class RexCorrelVariable
extends RexVariable

Reference to the current row of a correlating relational expression.

Correlating variables are introduced when performing nested loop joins. Each row is received from one side of the join, a correlating variable is assigned a value, and the other side of the join is restarted.

Since:

Nov 24, 2003

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rex/RexCorrelVariable.java#12 $

Author:

jhyde

Field Summary

Fields inherited from class org.eigenbase.rex.RexVariable

name, type

Fields inherited from class org.eigenbase.rex.RexNode

digest, EMPTY_ARRAY

Constructor Summary

RexCorrelVariable(String varName, RelDataType type)

Method Summary

<R> R	accept(RexVisitor<R> visitor) Accepts a visitor, dispatching to the right overloaded visitXxx method.
RexCorrelVariable	clone()

Methods inherited from class org.eigenbase.rex.RexVariable

getName, getType

Methods inherited from class org.eigenbase.rex.RexNode

getKind, isA, isAlwaysTrue, toString

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RexCorrelVariable

RexCorrelVariable(String varName,
                  RelDataType type)

Method Detail

clone

public RexCorrelVariable clone()

Specified by:

clone in class RexNode

accept

public <R> R accept(RexVisitor<R> visitor)

Description copied from class: RexNode

Accepts a visitor, dispatching to the right overloaded visitXxx method.

Also see RexProgram.apply(RexVisitor, RexNode[], RexNode), which applies a visitor to several expressions simultaneously.

Specified by:

accept in class RexNode