org.eigenbase.rel.metadata
Class RelColumnOrigin

java.lang.Object
  org.eigenbase.rel.metadata.RelColumnOrigin

public class RelColumnOrigin
extends Object

RelColumnOrigin is a data structure describing one of the origins of an output column produced by a relational expression.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/metadata/RelColumnOrigin.java#6 $

Author:

John V. Sichi

Field Summary

private int	iOriginColumn
private boolean	isDerived
private RelOptTable	originTable

Constructor Summary

RelColumnOrigin(RelOptTable originTable, int iOriginColumn, boolean isDerived)

Method Summary

boolean	equals(Object obj)
int	getOriginColumnOrdinal()
RelOptTable	getOriginTable()
int	hashCode()
boolean	isDerived() Consider the query select a+b as c, d as e from t.

Methods inherited from class java.lang.Object

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

Field Detail

originTable

private final RelOptTable originTable

iOriginColumn

private final int iOriginColumn

isDerived

private final boolean isDerived

Constructor Detail

RelColumnOrigin

public RelColumnOrigin(RelOptTable originTable,
                       int iOriginColumn,
                       boolean isDerived)

Method Detail

getOriginTable

public RelOptTable getOriginTable()

Returns:

table of origin

getOriginColumnOrdinal

public int getOriginColumnOrdinal()

Returns:

0-based index of column in origin table; whether this ordinal is flattened or unflattened depends on whether UDT flattening has already been performed on the relational expression which produced this description

isDerived

public boolean isDerived()

Consider the query select a+b as c, d as e from t. The output column c has two origins (a and b), both of them derived. The output column d as one origin (c), which is not derived.

Returns:

false if value taken directly from column in origin table; true otherwise

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object