org.eigenbase.rel
Class MinusRel

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

All Implemented Interfaces:

Cloneable, RelNode

public final class MinusRel
extends SetOpRel

MinusRel returns the rows of its first input minus any matching rows from its other inputs. If "all" is true, then multiset subtraction is performed; otherwise, set subtraction is performed (implying no duplicates in the results).

Since:

23 September, 2001

Version:

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

Author:

jhyde

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

MinusRel(RelOptCluster cluster, RelNode[] inputs, boolean all)

Method Summary

MinusRel	clone() Clones this RelNode.
MinusRel	clone(RelNode[] inputs, boolean all)
double	getRows() Returns an estimate of the number of rows this relational expression will return.

Methods inherited from class org.eigenbase.rel.SetOpRel

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

Methods inherited from class org.eigenbase.rel.AbstractRelNode

childrenAccept, 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

MinusRel

public MinusRel(RelOptCluster cluster,
                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

clone

public MinusRel clone()

Description copied from interface: RelNode

Clones this RelNode.

Traits of the RelNode must be explicitly cloned, using AbstractRelNode.inheritTraitsFrom(AbstractRelNode), as the RelNode may have traits of which it has no knowledge. Example implementation:

     public MyRelNode clone()
     {
         MyRelNode clone = new MyRelNode(...);
         clone.inheritTraitsFrom(this);
         return clone;
     }
 

N.B.: This method must be overridden whenever an existing, concrete RelNode is extended. Otherwise, calling clone() will produce a differently typed RelNode, resulting in invalid or incorrect query plans.

Specified by:

clone in interface RelNode

Specified by:

clone in class AbstractRelNode

Returns:

a clone of this RelNode

clone

public MinusRel clone(RelNode[] inputs,
                      boolean all)

Specified by:

clone in class SetOpRel