org.eigenbase.rel
Class UnionRelBase

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SetOpRel
          org.eigenbase.rel.UnionRelBase

All Implemented Interfaces:

Cloneable, RelNode

Direct Known Subclasses:

IterConcatenateRel, UnionRel

public abstract class UnionRelBase
extends SetOpRel

UnionRelBase is an abstract base class for implementations of UnionRel.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/UnionRelBase.java#8 $

Author:

John V. Sichi

Field Summary

Fields inherited from class org.eigenbase.rel.SetOpRel

all, inputs

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

UnionRelBase(RelOptCluster cluster, RelTraitSet traits, RelNode[] inputs, boolean all)

Method Summary

static double	estimateRowCount(RelNode rel) Helper method for computing row count for UNION ALL.
double	getRows() Returns an estimate of the number of rows this relational expression will return.

Methods inherited from class org.eigenbase.rel.SetOpRel

clone, deriveRowType, explain, getInputs, isDistinct, isHomogeneous, isHomogeneous, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

childrenAccept, 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, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

UnionRelBase

protected UnionRelBase(RelOptCluster cluster,
                       RelTraitSet traits,
                       RelNode[] inputs,
                       boolean all)

Method Detail

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

estimateRowCount

public static double estimateRowCount(RelNode rel)

Helper method for computing row count for UNION ALL.

Parameters:

rel - node representing UNION ALL

Returns:

estimated row count for rel