Class IntersectRel

  extended by org.eigenbase.rel.AbstractRelNode
      extended by org.eigenbase.rel.SetOpRel
          extended by org.eigenbase.rel.IntersectRel
All Implemented Interfaces:
Cloneable, RelNode

public final class IntersectRel
extends SetOpRel

IntersectRel returns the intersection of the rows of its inputs. If "all" is true, then multiset intersection is performed; otherwise, set intersection is performed (implying no duplicates in the results).

23 September, 2001
$Id: //open/dev/farrago/src/org/eigenbase/rel/ $

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
Constructor Summary
IntersectRel(RelOptCluster cluster, RelNode[] inputs, boolean all)
Method Summary
 IntersectRel clone()
          Clones this RelNode.
 IntersectRel 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


public IntersectRel(RelOptCluster cluster,
                    RelNode[] inputs,
                    boolean all)
Method Detail


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
getRows in class AbstractRelNode


public IntersectRel 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(...);
         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
a clone of this RelNode


public IntersectRel clone(RelNode[] inputs,
                          boolean all)
Specified by:
clone in class SetOpRel