net.sf.saffron.rel
Class UnionRel

java.lang.Object
  |
  +--net.sf.saffron.rel.SaffronRel
        |
        +--net.sf.saffron.rel.UnionRel

Direct Known Subclasses:

IntersectRel, IterConcatenateRel, JavaUnionAllRel, MinusRel

public class UnionRel

extends SaffronRel

UnionRel returns the union of the rows of its inputs, optionally eliminating duplicates.

Since:

23 September, 2001

Version:

$Id: //open/saffron/src/net/sf/saffron/rel/UnionRel.java#5 $

Author:

jhyde

Field Summary

protected boolean	all
protected SaffronRel[]	inputs

Fields inherited from class net.sf.saffron.rel.SaffronRel

cluster, digest, emptyArray, id, nextId, rowType

Constructor Summary

UnionRel(VolcanoCluster cluster, SaffronRel[] inputs, boolean all)

Method Summary

Object	clone()
protected SaffronType	deriveRowType()
void	explain(PlanWriter pw)
SaffronRel[]	getInputs() Returns an array of this SaffronRel's inputs.
double	getRows() Returns an estimate of the number of rows this relational expression will return.
boolean	isDistinct() Returns whether the same value will not come out twice.
void	replaceInput(int ordinalInParent, SaffronRel p) Replaces the ordinalInParentth input.

Methods inherited from class net.sf.saffron.rel.SaffronRel

childrenAccept, computeDigest, computeSelfCost, getChildExps, getCluster, getConvention, getCorrelVariable, getId, getInput, getOrCreateCorrelVariable, getQualifier, getQuery, getRelTypeName, getRowType, getTable, getVariablesStopped, implement, implementFieldAccess, isAccessTo, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

inputs

protected SaffronRel[] inputs

all

protected boolean all

Constructor Detail

UnionRel

public UnionRel(VolcanoCluster cluster,
                SaffronRel[] inputs,
                boolean all)

Method Detail

isDistinct

public boolean isDistinct()

Description copied from class: SaffronRel

Returns whether the same value will not come out twice. Default value is false, derived classes should override.

Overrides:

isDistinct in class SaffronRel

getInputs

public SaffronRel[] getInputs()

Description copied from class: SaffronRel

Returns an array of this SaffronRel's inputs. If there are no inputs, returns an empty array, not null.

Overrides:

getInputs in class SaffronRel

getRows

public double getRows()

Description copied from class: SaffronRel

Returns an estimate of the number of rows this relational expression will return.

Overrides:

getRows in class SaffronRel

clone

public Object clone()

Specified by:

clone in class SaffronRel

explain

public void explain(PlanWriter pw)

Overrides:

explain in class SaffronRel

replaceInput

public void replaceInput(int ordinalInParent,
                         SaffronRel p)

Description copied from class: SaffronRel

Replaces the ordinalInParent^th input. You must override this method if you override SaffronRel.getInputs().

Overrides:

replaceInput in class SaffronRel

deriveRowType

protected SaffronType deriveRowType()

Specified by:

deriveRowType in class SaffronRel