Class JoinResultSet

java.lang.Object

org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

org.apache.derby.impl.sql.execute.NoPutResultSetImpl

org.apache.derby.impl.sql.execute.JoinResultSet

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

Direct Known Subclasses:

MergeJoinResultSet, NestedLoopJoinResultSet

abstract class JoinResultSet
extends NoPutResultSetImpl
implements CursorResultSet

Takes 2 NoPutResultSets and a join filter and returns the join's rows satisfying the filter as a result set.

Nested Class Summary

Nested classes/interfaces inherited from class BasicNoPutResultSetImpl

BasicNoPutResultSetImpl.FieldComparator

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	isRightOpen
protected int	leftNumCols
NoPutResultSet	leftResultSet
protected ExecRow	leftRow
protected ExecRow	mergedRow
boolean	notExistsRightSide
boolean	oneRowRightSide
protected GeneratedMethod	restriction
long	restrictionTime
protected int	rightNumCols
NoPutResultSet	rightResultSet
protected ExecRow	rightRow
int	rowsReturned
int	rowsSeenLeft
int	rowsSeenRight
(package private) String	userSuppliedOptimizerOverrides

Fields inherited from class NoPutResultSetImpl

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from class BasicNoPutResultSetImpl

activation, beginTime, closeTime, compactRow, constructorTime, currentRow, endExecutionTime, finished, isOpen, isTopResultSet, nextTime, numOpens, openTime, optimizerEstimatedCost, optimizerEstimatedRowCount, resultDescription, rowsFiltered, rowsSeen, startExecutionTime, subqueryTrackingArray

Fields inherited from interface NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE, TEMPORARY_RESULT_SET_NUMBER

Fields inherited from interface ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

Constructors

Constructor	Description
JoinResultSet(NoPutResultSet leftResultSet, int leftNumCols, NoPutResultSet rightResultSet, int rightNumCols, Activation activation, GeneratedMethod restriction, int resultSetNumber, boolean oneRowRightSide, boolean notExistsRightSide, double optimizerEstimatedRowCount, double optimizerEstimatedCost, String userSuppliedOptimizerOverrides)

Method Summary

Modifier and Type	Method	Description
(package private) void	clearScanState()	Clear any private state that changes during scans.
void	close()	If the result set has been opened, close the open scan.
protected void	closeRight()	close the rightResultSet
void	finish()	Tells the system that there will be no more access to any database information via this result set; in particular, no more calls to open().
ExecRow	getCurrentRow()	A join is combining rows from two sources, so it should never be used in a positioned update or delete.
RowLocation	getRowLocation()	A join is combining rows from two sources, so it has no single row location to return; just return a null.
void	openCore()	open a scan on the join.
protected void	openRight()	open the rightResultSet.
void	reopenCore()	reopen a a join.

Methods inherited from class NoPutResultSetImpl

clearCurrentRow, clearOrderableCache, closeRowSource, getCursorName, getNextRowFromRowSource, getResultDescription, getValidColumns, isForUpdate, markRowAsDeleted, needsRowLocation, needsRowLocationForDeferredCheckConstraints, needsToClone, offendingRowLocation, positionScanAtRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setHasDeferrableChecks, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, unpackHashValue, updateRow

Methods inherited from class BasicNoPutResultSetImpl

addWarning, attachStatementContext, checkCancellationFlag, checkRowPosition, childrenToXML, cleanUp, dumpTimeStats, finishAndRTS, getAbsoluteRow, getActivation, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCompactRow, getCurrentTimeMillis, getElapsedMillis, getEndExecutionTimestamp, getEstimatedRowCount, getExecuteTime, getExecutionFactory, getFirstRow, getLanguageConnectionContext, getLastRow, getNextRow, getNextRowCore, getPointOfAttachment, getPreviousRow, getRelativeRow, getRowNumber, getScanIsolationLevel, getSubqueryTrackingArray, getTransactionController, getWarnings, isClosed, isXplainOnlyMode, markAsTopResultSet, modifiedRowCount, open, recordConstructorTime, requiresRelocking, returnsRows, setAfterLastRow, setBeforeFirstRow, setCompactRow, setCompatRow, toXML, toXML

Methods inherited from class Object

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

Methods inherited from interface ResultSet

addWarning, checkRowPosition, cleanUp, clearCurrentRow, getAbsoluteRow, getActivation, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCursorName, getEndExecutionTimestamp, getExecuteTime, getFirstRow, getLastRow, getNextRow, getPreviousRow, getRelativeRow, getResultDescription, getRowNumber, getSubqueryTrackingArray, getTimeSpent, getWarnings, isClosed, modifiedRowCount, open, returnsRows, setAfterLastRow, setBeforeFirstRow, toXML

Field Details

rowsSeenLeft

public int rowsSeenLeft

rowsSeenRight

public int rowsSeenRight

rowsReturned

public int rowsReturned

restrictionTime

public long restrictionTime

isRightOpen

protected boolean isRightOpen

leftRow

protected ExecRow leftRow

rightRow

protected ExecRow rightRow

mergedRow

protected ExecRow mergedRow

leftResultSet

public NoPutResultSet leftResultSet

leftNumCols

protected int leftNumCols

rightResultSet

public NoPutResultSet rightResultSet

rightNumCols

protected int rightNumCols

restriction

protected GeneratedMethod restriction

oneRowRightSide

public boolean oneRowRightSide

notExistsRightSide

public boolean notExistsRightSide

userSuppliedOptimizerOverrides

String userSuppliedOptimizerOverrides

Constructor Details

JoinResultSet

JoinResultSet(NoPutResultSet leftResultSet,
 int leftNumCols,
 NoPutResultSet rightResultSet,
 int rightNumCols,
 Activation activation,
 GeneratedMethod restriction,
 int resultSetNumber,
 boolean oneRowRightSide,
 boolean notExistsRightSide,
 double optimizerEstimatedRowCount,
 double optimizerEstimatedCost,
 String userSuppliedOptimizerOverrides)

Method Details

clearScanState

void clearScanState()

Clear any private state that changes during scans. This includes things like the last row seen, etc. THis does not include immutable things that are typically set up in the constructor.

This method is called on open()/close() and reopen()

openCore

public void openCore()
              throws StandardException

open a scan on the join. For a join, this means: o Open the left ResultSet o Do a getNextRow() on the left ResultSet to establish a position and get "parameter values" for the right ResultSet. NOTE: It is possible for the getNextRow() to return null, in which case there is no need to open the RightResultSet. We must remember this condition. o If the getNextRow() on the left ResultSet succeeded, then open() the right ResultSet. scan parameters are evaluated at each open, so there is probably some way of altering their values...

Specified by:

openCore in interface NoPutResultSet

Throws:

StandardException - Thrown on error

reopenCore

public void reopenCore()
                throws StandardException

reopen a a join.

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class BasicNoPutResultSetImpl

Throws:

StandardException - thrown if cursor finished.

See Also:

• NoPutResultSet.openCore()

close

public void close()
           throws StandardException

If the result set has been opened, close the open scan. WARNING does not track close time, since it is expected to be called directly by its subclasses, and we don't want to skew the times

Specified by:

close in interface ResultSet

Overrides:

close in class NoPutResultSetImpl

Throws:

StandardException - thrown on error

finish

public void finish()
            throws StandardException

Description copied from interface: ResultSet

Tells the system that there will be no more access to any database information via this result set; in particular, no more calls to open(). Will close the result set if it is not already closed.

Specified by:

finish in interface ResultSet

Overrides:

finish in class BasicNoPutResultSetImpl

Throws:

StandardException - on error

getRowLocation

public RowLocation getRowLocation()

A join is combining rows from two sources, so it has no single row location to return; just return a null.

Specified by:

getRowLocation in interface CursorResultSet

Returns:

the row location of the current cursor row.

See Also:

• CursorResultSet

getCurrentRow

public ExecRow getCurrentRow()

A join is combining rows from two sources, so it should never be used in a positioned update or delete.

Specified by:

getCurrentRow in interface CursorResultSet

Returns:

a null value.

See Also:

• CursorResultSet

openRight

protected void openRight()
                  throws StandardException

open the rightResultSet. If already open, just reopen.

Throws:

StandardException - Thrown on error

closeRight

protected void closeRight()
                   throws StandardException

close the rightResultSet

Throws:

StandardException