org.eigenbase.rel
Class SingleRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel

All Implemented Interfaces:

Cloneable, RelNode

Direct Known Subclasses:

AggregateRelBase, CalcRelBase, CollectRel, ConverterRelImpl, FarragoIndexBuilderRel, FennelSingleRel, FilterRelBase, IterCalcRel, ProjectRelBase, SamplingRel, SortRel, TableModificationRelBase, UncollectRel, VolcanoPlannerTest.TestSingleRel, VolcanoPlannerTraitTest.TestSingleRel, WindowedAggregateRel

public abstract class SingleRel
extends AbstractRelNode

A SingleRel is a base class single-input relational expressions.

Since:

23 September, 2001

Version:

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

Author:

jhyde

Field Summary

private RelNode

child

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

protected

SingleRel(RelOptCluster cluster, RelTraitSet traits, RelNode child) Creates a SingleRel.

Method Summary

void	childrenAccept(RelVisitor visitor) Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.
protected RelDataType	deriveRowType()
void	explain(RelOptPlanWriter pw)
RelNode	getChild()
RelNode[]	getInputs() Returns an array of this relational expression's inputs.
double	getRows() Returns an estimate of the number of rows this relational expression will return.
void	replaceInput(int ordinalInParent, RelNode rel) Replaces the ordinalInParentth input.

Methods inherited from class org.eigenbase.rel.AbstractRelNode

clone, cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

child

private RelNode child

Constructor Detail

SingleRel

protected SingleRel(RelOptCluster cluster,
                    RelTraitSet traits,
                    RelNode child)

Creates a SingleRel.

Parameters:

cluster - RelOptCluster this relational expression belongs to

child - input relational expression

Method Detail

getChild

public RelNode getChild()

getInputs

public RelNode[] getInputs()

Description copied from interface: RelNode

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

Specified by:

getInputs in interface RelNode

Overrides:

getInputs in class AbstractRelNode

getRows

public double getRows()

Description copied from interface: RelNode

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

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getRowCount(org.eigenbase.rel.RelNode), which gives plugins a chance to override the rel's default ideas about row count.

Specified by:

getRows in interface RelNode

Overrides:

getRows in class AbstractRelNode

childrenAccept

public void childrenAccept(RelVisitor visitor)

Description copied from interface: RelNode

Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.

Specified by:

childrenAccept in interface RelNode

Overrides:

childrenAccept in class AbstractRelNode

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class AbstractRelNode

replaceInput

public void replaceInput(int ordinalInParent,
                         RelNode rel)

Description copied from interface: RelNode

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

Specified by:

replaceInput in interface RelNode

Overrides:

replaceInput in class AbstractRelNode

deriveRowType

protected RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode