org.eigenbase.rel
Class TableAccessRelBase

java.lang.Object
  extended by org.eigenbase.rel.AbstractRelNode
      extended by 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