org.apache.derby.impl.sql.execute

Class DistinctScanResultSet

java.lang.Object

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

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

org.apache.derby.impl.sql.execute.ScanResultSet

org.apache.derby.impl.sql.execute.HashScanResultSet

org.apache.derby.impl.sql.execute.DistinctScanResultSet

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

class DistinctScanResultSet
extends HashScanResultSet

Eliminates duplicates while scanning the underlying conglomerate. (Assumes no predicates, for now.)

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.Enumeration	element

Fields inherited from class org.apache.derby.impl.sql.execute.HashScanResultSet

compactRow, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOADFACTOR, DEFAULT_MAX_CAPACITY, eliminateDuplicates, firstNext, forUpdate, hashtable, hashtableSize, indexName, isConstraint, keyColumns, nextQualifiers, scanProperties, scanQualifiers, scoci, startPositionString, stopPositionString, tableName, userSuppliedOptimizerOverrides

Fields inherited from class org.apache.derby.impl.sql.execute.ScanResultSet

accessedCols, candidate, isolationLevel, lockMode, resultRowBuilder

Fields inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from class org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

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

Fields inherited from interface org.apache.derby.iapi.sql.ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Fields inherited from interface org.apache.derby.iapi.sql.execute.NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE

Constructor Summary

Constructors

Constructor and Description

DistinctScanResultSet(long conglomId, StaticCompiledOpenConglomInfo scoci, Activation activation, int resultRowTemplate, int resultSetNumber, int hashKeyItem, java.lang.String tableName, java.lang.String userSuppliedOptimizerOverrides, java.lang.String indexName, boolean isConstraint, int colRefItem, int lockMode, boolean tableLocked, int isolationLevel, double optimizerEstimatedRowCount, double optimizerEstimatedCost)

Method Summary

Modifier and Type	Method and Description
ExecRow	getNextRowCore() Return the next row (if any) from the scan (if open).

Methods inherited from class org.apache.derby.impl.sql.execute.HashScanResultSet

canGetInstantaneousLocks, close, getCurrentRow, getRowLocation, getScanProperties, getTimeSpent, isForUpdate, openCore, printStartPosition, printStopPosition, reopenCore, requiresRelocking

Methods inherited from class org.apache.derby.impl.sql.execute.ScanResultSet

getScanIsolationLevel, initIsolationLevel

Methods inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl

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

Methods inherited from class org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.sql.ResultSet

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

Field Detail

element

java.util.Enumeration element

Constructor Detail

DistinctScanResultSet

DistinctScanResultSet(long conglomId,
                      StaticCompiledOpenConglomInfo scoci,
                      Activation activation,
                      int resultRowTemplate,
                      int resultSetNumber,
                      int hashKeyItem,
                      java.lang.String tableName,
                      java.lang.String userSuppliedOptimizerOverrides,
                      java.lang.String indexName,
                      boolean isConstraint,
                      int colRefItem,
                      int lockMode,
                      boolean tableLocked,
                      int isolationLevel,
                      double optimizerEstimatedRowCount,
                      double optimizerEstimatedCost)
               throws StandardException

Throws:

StandardException

Method Detail

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

Return the next row (if any) from the scan (if open).

Specified by:

getNextRowCore in interface NoPutResultSet

Overrides:

getNextRowCore in class HashScanResultSet

Returns:

the next row in the result

Throws:

StandardException - thrown on failure to get next row

See Also:

NoPutResultSet.getNextRowCore()