org.eigenbase.rel
Class TableAccessRelBase

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

All Implemented Interfaces:

Cloneable, RelNode

Direct Known Subclasses:

FlatFileFennelRel, FtrsIndexScanRel, MedMdrClassExtentRel, MedMockFennelRel, MedMockIterRel, MedMqlTableRel, TableAccessRel

public abstract class TableAccessRelBase
extends AbstractRelNode

TableAccessRelBase is an abstract base class for implementations of TableAccessRel.

Version:

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

Author:

John V. Sichi

Field Summary

protected RelOptConnection	connection The connection to the optimizing session.
protected RelOptTable	table The table definition.

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

TableAccessRelBase(RelOptCluster cluster, RelTraitSet traits, RelOptTable table, RelOptConnection connection)

Method Summary

TableAccessRelBase	clone() Clones this RelNode.
RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
RelDataType	deriveRowType()
void	explain(RelOptPlanWriter pw)
List<RelCollation>	getCollationList() Returns a description of the physical ordering (or orderings) of this relational expression.
RelOptConnection	getConnection()
double	getRows() Returns an estimate of the number of rows this relational expression will return.
RelOptTable	getTable() If this relational expression represents an access to a table, returns that table, otherwise returns null.

Methods inherited from class org.eigenbase.rel.AbstractRelNode

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

Methods inherited from class java.lang.Object

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

Field Detail

connection

protected RelOptConnection connection

The connection to the optimizing session.

table

protected RelOptTable table

The table definition.

Constructor Detail

TableAccessRelBase

protected TableAccessRelBase(RelOptCluster cluster,
                             RelTraitSet traits,
                             RelOptTable table,
                             RelOptConnection connection)

Method Detail

getConnection

public RelOptConnection getConnection()

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

getTable

public RelOptTable getTable()

Description copied from interface: RelNode

If this relational expression represents an access to a table, returns that table, otherwise returns null.

Specified by:

getTable in interface RelNode

Overrides:

getTable in class AbstractRelNode

getCollationList

public List<RelCollation> getCollationList()

Description copied from interface: RelNode

Returns a description of the physical ordering (or orderings) of this relational expression.

Specified by:

getCollationList in interface RelNode

Overrides:

getCollationList in class AbstractRelNode

clone

public TableAccessRelBase 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

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner)

Description copied from interface: RelNode

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

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

Specified by:

computeSelfCost in interface RelNode

Overrides:

computeSelfCost in class AbstractRelNode

deriveRowType

public RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class AbstractRelNode