org.apache.derby.impl.sql.compile
Class HalfOuterJoinNode

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ResultSetNode
          org.apache.derby.impl.sql.compile.FromTable
              org.apache.derby.impl.sql.compile.TableOperatorNode
                  org.apache.derby.impl.sql.compile.JoinNode
                      org.apache.derby.impl.sql.compile.HalfOuterJoinNode

All Implemented Interfaces:

Optimizable, Visitable

public class HalfOuterJoinNode

extends JoinNode

An HalfOuterJoinNode represents a left or a right outer join result set. Right outer joins are always transformed into left outer joins during preprocessing for simplicity.

Author:

Jerry Brenner

Field Summary

private boolean	rightOuterJoin
private boolean	transformed

Fields inherited from class org.apache.derby.impl.sql.compile.JoinNode

aggregateVector, CROSSJOIN, flattenableJoin, FULLOUTERJOIN, INNERJOIN, joinClause, joinClauseNormalized, joinPredicates, LEFTOUTERJOIN, RIGHTOUTERJOIN, subqueryList, UNIONJOIN, usingClause

Fields inherited from class org.apache.derby.impl.sql.compile.TableOperatorNode

leftOptimizer, leftResultSet, nestedInParens, rightOptimizer, rightResultSet

Fields inherited from class org.apache.derby.impl.sql.compile.FromTable

bestAccessPath, bestCostEstimate, bestSortAvoidancePath, correlationName, corrTableName, currentAccessPath, hashKeyColumns, initialCapacity, level, loadFactor, maxCapacity, tableNumber, tableProperties, trulyTheBestAccessPath, userSpecifiedJoinStrategy

Fields inherited from class org.apache.derby.impl.sql.compile.ResultSetNode

costEstimate, cursorTargetTable, insertSource, optimizer, referencedTableMap, resultColumns, resultSetNumber, scratchCostEstimate, statementResultSet

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, beginOffset, endOffset

Constructor Summary

HalfOuterJoinNode()

Method Summary

protected int	addOuterJoinArguments(ActivationClassBuilder acb, MethodBuilder mb) Generate and add any arguments specifict to outer joins.
protected void	adjustNumberOfRowsReturned(CostEstimate costEstimate) Some types of joins (e.g. outer joins) will return a different number of rows than is predicted by optimizeIt() in JoinNode.
void	generate(ActivationClassBuilder acb, MethodBuilder mb) Generate the code for an inner join node.
(package private) ResultSetNode	getLogicalLeftResultSet() Return the logical left result set for this qualified join node.
(package private) ResultSetNode	getLogicalRightResultSet() Return the logical right result set for this qualified join node.
protected int	getNumJoinArguments() Return the number of arguments to the join result set.
void	init(java.lang.Object leftResult, java.lang.Object rightResult, java.lang.Object onClause, java.lang.Object usingClause, java.lang.Object rightOuterJoin, java.lang.Object tableProperties) Initializer for a HalfOuterJoinNode.
boolean	isRightOuterJoin() Return true if right outer join or false if left outer join Used to set Nullability correctly in JoinNode
boolean	LOJ_bindResultColumns(boolean anyChange)
boolean	LOJ_reorderable(int numTables) This method determines if (1) the query is a LOJ, and (2) if the LOJ is a candidate for reordering (i.e., linearization).
JBitSet	LOJgetNPReferencedTables(int numTables)
protected void	oneRowRightSide(ActivationClassBuilder acb, MethodBuilder mb)
ResultSetNode	preprocess(int numTables, GroupByList gbl, FromList fromList) Put a ProjectRestrictNode on top of each FromTable in the FromList.
void	pushExpressions(PredicateList outerPredicateList) Push expressions down to the first ResultSetNode which can do expression evaluation and has the same referenced table map.
boolean	pushOptPredicate(OptimizablePredicate optimizablePredicate) Push an OptimizablePredicate down, if this node accepts it.
java.lang.String	toString() Convert this object to a String.
FromTable	transformOuterJoins(ValueNode predicateTree, int numTables) Transform any Outer Join into an Inner Join where applicable.

Methods inherited from class org.apache.derby.impl.sql.compile.JoinNode

accept, bindResultColumns, bindResultColumns, flatten, generateCore, generateCore, getAllResultColumns, getLeftPredicateList, getMatchingColumn, getRightPredicateList, isFlattenableJoinNode, isOrderedOn, joinTypeToString, LOJgetReferencedTables, modifyAccessPath, normExpressions, notFlattenableJoin, optimizeIt, printSubNodes, projectResultColumns, pushExpressionsToLeft, setAggregateVector, setSubqueryList, updateTargetLockMode

Methods inherited from class org.apache.derby.impl.sql.compile.TableOperatorNode

bindExpressions, bindExpressionsWithTables, bindNonVTITables, bindVTITables, decrementLevel, getExposedName, getFromTableByName, getLeftmostResultSet, getLeftResultSet, getNestedInParens, getRightResultSet, init, markOrderingDependent, modifyAccessPaths, needsSpecialRCLBinding, optimize, optimizeSource, referencesSessionSchema, referencesTarget, rejectParameters, replaceDefaults, setLeftmostResultSet, setLevel, setNestedInParens, setReferencedColumns, verifyProperties

Methods inherited from class org.apache.derby.impl.sql.compile.FromTable

areAllColumnsProjected, assignCostEstimate, canBeOrdered, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, forUpdate, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCostEstimate, getCurrentAccessPath, getLevel, getName, getNumColumnsReturned, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getTrulyTheBestAccessPath, getUserSpecifiedJoinStrategy, hashKeyColumns, hasTableNumber, init, initAccessPaths, initialCapacity, isBaseTable, isCoveringIndex, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, markUpdatableByCursor, maxCapacity, memoryUsageOK, nextAccessPath, optimizeSubqueries, pullOptPredicates, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setAllColumnsProjected, setCostEstimate, setHashKeyColumns, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, uniqueJoin

Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode

addNewPredicate, assignResultSetNumber, bindTargetExpressions, bindUntypedNullsToResultColumns, changeAccessPath, closeMethodArgument, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, ensurePredicateList, flattenableInFromSubquery, generateNormalizationResultSet, generateResultSet, genNewRCForInsert, genNormalizeResultSetNode, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getCostEstimate, getCursorTargetTable, getFinalCostEstimate, getFromList, getNewCostEstimate, getOptimizer, getReferencedTableMap, getResultColumns, getResultSetNumber, isNotExists, isOneRowResultSet, isPossibleDistinctScan, isUpdatableCursor, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, notCursorTargetTable, numDistinctAggregates, parseDefault, performMaterialization, pushOrderByList, rejectXMLValues, renameGeneratedResultNames, returnsAtMostOneRow, setInsertSource, setReferencedTableMap, setResultColumns, setResultToBooleanTrueNode, setTableConstructorTypes, subqueryReferencesTarget, verifySelectStarSubquery

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getSPSName, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.sql.compile.Optimizable

getDataDictionary, getReferencedTableMap, getResultSetNumber

Field Detail

rightOuterJoin

private boolean rightOuterJoin

transformed

private boolean transformed

Constructor Detail

HalfOuterJoinNode

public HalfOuterJoinNode()

Method Detail

init

public void init(java.lang.Object leftResult,
                 java.lang.Object rightResult,
                 java.lang.Object onClause,
                 java.lang.Object usingClause,
                 java.lang.Object rightOuterJoin,
                 java.lang.Object tableProperties)
          throws StandardException

Initializer for a HalfOuterJoinNode.

Overrides:

init in class JoinNode

Parameters:

leftResult - The ResultSetNode on the left side of this join

rightResult - The ResultSetNode on the right side of this join

onClause - The ON clause

usingClause - The USING clause

rightOuterJoin - Whether or not this node represents a user specified right outer join

tableProperties - Properties list associated with the table

Throws:

StandardException - Thrown on error

pushOptPredicate

public boolean pushOptPredicate(OptimizablePredicate optimizablePredicate)
                         throws StandardException

Description copied from interface: Optimizable

Push an OptimizablePredicate down, if this node accepts it.

Specified by:

pushOptPredicate in interface Optimizable

Overrides:

pushOptPredicate in class JoinNode

Throws:

StandardException - Thrown on error

See Also:

Optimizable.pushOptPredicate(org.apache.derby.iapi.sql.compile.OptimizablePredicate)

toString

public java.lang.String toString()

Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Overrides:

toString in class TableOperatorNode

Returns:

This object as a String

preprocess

public ResultSetNode preprocess(int numTables,
                                GroupByList gbl,
                                FromList fromList)
                         throws StandardException

Put a ProjectRestrictNode on top of each FromTable in the FromList. ColumnReferences must continue to point to the same ResultColumn, so that ResultColumn must percolate up to the new PRN. However, that ResultColumn will point to a new expression, a VirtualColumnNode, which points to the FromTable and the ResultColumn that is the source for the ColumnReference. (The new PRN will have the original of the ResultColumnList and the ResultColumns from that list. The FromTable will get shallow copies of the ResultColumnList and its ResultColumns. ResultColumn.expression will remain at the FromTable, with the PRN getting a new VirtualColumnNode for each ResultColumn.expression.) We then project out the non-referenced columns. If there are no referenced columns, then the PRN's ResultColumnList will consist of a single ResultColumn whose expression is 1.

Overrides:

preprocess in class JoinNode

Parameters:

numTables - Number of tables in the DML Statement

gbl - The group by list, if any

fromList - The from list, if any

Returns:

The generated ProjectRestrictNode atop the original FromTable.

Throws:

StandardException - Thrown on error

pushExpressions

public void pushExpressions(PredicateList outerPredicateList)
                     throws StandardException

Push expressions down to the first ResultSetNode which can do expression evaluation and has the same referenced table map. RESOLVE - This means only pushing down single table expressions to DistinctNodes today. Once we have a better understanding of how the optimizer will work, we can push down join clauses.

Overrides:

pushExpressions in class JoinNode

Parameters:

outerPredicateList - The PredicateList from the outer RS.

Throws:

StandardException - Thrown on error

LOJ_reorderable

public boolean LOJ_reorderable(int numTables)
                        throws StandardException

This method determines if (1) the query is a LOJ, and (2) if the LOJ is a candidate for reordering (i.e., linearization). The condition for LOJ linearization is: 1. only LOJ in the fromList, i.e., no INNER, no FULL JOINs, no ROJs 2. ON clause must be equality join between left and right operands and in CNF (i.e., AND is allowed)

Overrides:

LOJ_reorderable in class JoinNode

Throws:

StandardException

LOJ_bindResultColumns

public boolean LOJ_bindResultColumns(boolean anyChange)
                              throws StandardException

Throws:

StandardException

transformOuterJoins

public FromTable transformOuterJoins(ValueNode predicateTree,
                                     int numTables)
                              throws StandardException

Transform any Outer Join into an Inner Join where applicable. (Based on the existence of a null intolerant predicate on the inner table.)

Overrides:

transformOuterJoins in class JoinNode

Parameters:

predicateTree - The predicate tree for the query block

Returns:

The new tree top (OuterJoin or InnerJoin).

Throws:

StandardException - Thrown on error

adjustNumberOfRowsReturned

protected void adjustNumberOfRowsReturned(CostEstimate costEstimate)

Description copied from class: JoinNode

Some types of joins (e.g. outer joins) will return a different number of rows than is predicted by optimizeIt() in JoinNode. So, adjust this value now. This method does nothing for most join types.

Overrides:

adjustNumberOfRowsReturned in class JoinNode

See Also:

JoinNode.adjustNumberOfRowsReturned(org.apache.derby.iapi.sql.compile.CostEstimate)

generate

public void generate(ActivationClassBuilder acb,
                     MethodBuilder mb)
              throws StandardException

Generate the code for an inner join node.

Overrides:

generate in class JoinNode

Throws:

StandardException - Thrown on error

addOuterJoinArguments

protected int addOuterJoinArguments(ActivationClassBuilder acb,
                                    MethodBuilder mb)
                             throws StandardException

Generate and add any arguments specifict to outer joins. Generate the methods (and add them as parameters) for returning an empty row from 1 or more sides of an outer join, if required. Pass whether or not this was originally a right outer join.

Overrides:

addOuterJoinArguments in class JoinNode

Parameters:

acb - The ActivationClassBuilder

mb - the method the generate code is to go into return The args that have been added

Throws:

StandardException - Thrown on error

getNumJoinArguments

protected int getNumJoinArguments()

Return the number of arguments to the join result set.

Overrides:

getNumJoinArguments in class JoinNode

oneRowRightSide

protected void oneRowRightSide(ActivationClassBuilder acb,
                               MethodBuilder mb)

Overrides:

oneRowRightSide in class JoinNode

getLogicalLeftResultSet

ResultSetNode getLogicalLeftResultSet()

Return the logical left result set for this qualified join node. (For RIGHT OUTER JOIN, the left is the right and the right is the left and the JOIN is the NIOJ).

Overrides:

getLogicalLeftResultSet in class JoinNode

getLogicalRightResultSet

ResultSetNode getLogicalRightResultSet()

Return the logical right result set for this qualified join node. (For RIGHT OUTER JOIN, the left is the right and the right is the left and the JOIN is the NIOJ).

Overrides:

getLogicalRightResultSet in class JoinNode

isRightOuterJoin

public boolean isRightOuterJoin()

Return true if right outer join or false if left outer join Used to set Nullability correctly in JoinNode

LOJgetNPReferencedTables

public JBitSet LOJgetNPReferencedTables(int numTables)
                                 throws StandardException

Throws:

StandardException