net.sf.farrago.query
Class FarragoColumnMetadata

java.lang.Object
  net.sf.farrago.namespace.impl.MedAbstractColumnMetadata
      net.sf.farrago.query.FarragoColumnMetadata

public class FarragoColumnMetadata
extends MedAbstractColumnMetadata

FarragoColumnMetadata is a default Farrago implementation of MedAbstractColumnMetadata for table level RelNodes. Note that it does not account for projection or UDTs.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/query/FarragoColumnMetadata.java#8 $

Author:

Zelaine Fong

Constructor Summary

FarragoColumnMetadata()

Method Summary

protected int	mapColumnToField(RelNode rel, FemAbstractColumn keyCol) Maps a FemAbstractColumn to its corresponding field reference in the RelNode.
protected FemAbstractColumn	mapFieldToColumn(RelNode rel, int fieldNo) Maps a field reference to its underlying FemAbstractColumn
protected int	mapFieldToColumnOrdinal(RelNode rel, int fieldNo) Maps a field reference to the underlying column ordinal corresponding to the FemAbstractColumn representing the column.
private int	numColumns(RelNode rel)

Methods inherited from class net.sf.farrago.namespace.impl.MedAbstractColumnMetadata

areColumnsUnique, areColumnsUnique, areColumnsUniqueForKeys, getDistinctRowCount, getPopulationSize, getUniqueKeys, getUniqueKeys

Methods inherited from class java.lang.Object

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

Constructor Detail

FarragoColumnMetadata

public FarragoColumnMetadata()

Method Detail

mapColumnToField

protected int mapColumnToField(RelNode rel,
                               FemAbstractColumn keyCol)

Description copied from class: MedAbstractColumnMetadata

Maps a FemAbstractColumn to its corresponding field reference in the RelNode.

Specified by:

mapColumnToField in class MedAbstractColumnMetadata

Parameters:

rel - RelNode corresponding to the column

keyCol - the column whose field ordinal will be returned

Returns:

field ordinal relative to the RelNode; -1 if the column is not accessed by the RelNode

mapFieldToColumnOrdinal

protected int mapFieldToColumnOrdinal(RelNode rel,
                                      int fieldNo)

Description copied from class: MedAbstractColumnMetadata

Maps a field reference to the underlying column ordinal corresponding to the FemAbstractColumn representing the column.

Specified by:

mapFieldToColumnOrdinal in class MedAbstractColumnMetadata

Parameters:

rel - RelNode corresponding to the column

fieldNo - the ordinal of the field reference

Returns:

column ordinal of the underlying FemAbstractColumn; -1 if the column does not map to actual FemAbstractColumn

mapFieldToColumn

protected FemAbstractColumn mapFieldToColumn(RelNode rel,
                                             int fieldNo)

Description copied from class: MedAbstractColumnMetadata

Maps a field reference to its underlying FemAbstractColumn

Specified by:

mapFieldToColumn in class MedAbstractColumnMetadata

Parameters:

rel - RelNode corresponding to the field

fieldNo - the ordinal of the field reference

Returns:

underlying FemAbstractColumn; null if no underlying FemAbstractColumn

numColumns

private int numColumns(RelNode rel)