Class CurrentOfNode
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.CurrentOfNode
- All Implemented Interfaces:
Optimizable
,Visitable
The CurrentOf operator is used by positioned DELETE
and UPDATE to get the current row and location
for the target cursor. The bind() operations for
positioned DELETE and UPDATE add a column to
the select list under the statement for the row location
accessible from this node.
This node is placed in the from clause of the select
generated for the delete or update operation. It acts
much like a FromBaseTable, using the information about
the target table of the cursor to provide information.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
ResultSetNode.QueryExpressionClauses
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate TableName
private String
private FromBaseTable
private TableName
private ExecPreparedStatement
private CostEstimate
Fields inherited from class org.apache.derby.impl.sql.compile.FromTable
ADD_PLAN, bestAccessPath, bestCostEstimate, bestSortAvoidancePath, correlationName, corrTableName, currentAccessPath, hashKeyColumns, initialCapacity, level, LOAD_PLAN, loadFactor, maxCapacity, origTableName, REMOVE_PLAN, tableNumber, tableProperties, trulyTheBestAccessPath, userSpecifiedJoinStrategy
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX
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Constructor Summary
ConstructorsConstructorDescriptionCurrentOfNode
(String correlationName, String cursor, Properties tableProperties, ContextManager cm) -
Method Summary
Modifier and TypeMethodDescription(package private) void
Accept the visitor for all visitable children of this node.(package private) void
bindExpressions
(FromList fromListParam) Bind the expressions in this ResultSetNode.(package private) ResultSetNode
bindNonVTITables
(DataDictionary dataDictionary, FromList fromListParam) Binding this FromTable means finding the prepared statement for the cursor and creating the result columns (the columns updatable on that cursor).estimateCost
(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering) Estimate the cost of scanning this Optimizable using the given predicate list with the given conglomerate.(package private) void
generate
(ActivationClassBuilder acb, MethodBuilder mb) Generation on a CurrentOfNode creates a scan on the cursor, CurrentOfResultSet.(package private) TableName
(package private) String
(package private) ExecPreparedStatement
Return the CursorNode associated with a positioned update/delete.(package private) String
Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.(package private) TableName
(package private) ResultColumn
getMatchingColumn
(ColumnReference columnReference) Try to find a ResultColumn in the table represented by this CurrentOfNode that matches the name in the given ColumnReference.(package private) static CurrentOfNode
makeForMerge
(String cursorName, FromBaseTable dummyTargetTable, ContextManager cm) Construct a dummy CurrentOfNode just for compiling the DELETE action of a MERGE statement.(package private) ResultSetNode
optimize
(DataDictionary dataDictionary, PredicateList predicateList, double outerRows) Optimize this CurrentOfNode.(package private) ResultSetNode
preprocess
(int numTables, GroupByList gbl, FromList fromList) Preprocess a CurrentOfNode.(package private) void
printSubNodes
(int depth) Prints the sub-nodes of this object.toString()
Convert this object to a String.int
Get the lock mode for this table as the target of an update statement (a delete or update).Methods inherited from class org.apache.derby.impl.sql.compile.FromTable
assignCostEstimate, canBeOrdered, columnsAreUpdatable, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, decrementLevel, feasibleJoinStrategy, fillInReferencedTableMap, flatten, forUpdate, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCorrelationName, getCostEstimate, getCurrentAccessPath, getFinalCostEstimate, getFromTableByName, getLevel, getMergeTableID, getName, getNumColumnsReturned, getOrigTableName, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getTrulyTheBestAccessPath, getUserSpecifiedJoinStrategy, hashKeyColumns, hasLargeObjectColumns, hasTableNumber, initAccessPaths, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isJoinColumnForRightOuterJoin, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeIt, optimizeSubqueries, pullOptPredicates, pushExpressions, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setCostEstimateCost, setHashKeyColumns, setLevel, setMergeTableID, setOrigTableName, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, transformOuterJoins, uniqueJoin, updateBestPlanMap, verifyProperties
Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
addNewPredicate, adjustForSortElimination, adjustForSortElimination, assignResultSetNumber, bindExpressionsWithTables, bindResultColumns, bindResultColumns, bindTargetExpressions, bindUntypedNullsToResultColumns, bindVTITables, changeAccessPath, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, ensurePredicateList, flattenableInFromSubquery, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCandidateFinalCostEstimate, getCostEstimate, getCursorTargetTable, getFromList, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, getScratchCostEstimate, isCursorTargetTable, isInsertSource, isNotExists, isOneRowResultSet, isOrderedOn, isPossibleDistinctScan, isStatementResultSet, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, modifyAccessPaths, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, performMaterialization, printQueryExpressionSuffixClauses, projectResultColumns, pushOffsetFetchFirst, pushOrderByList, pushQueryExpressionSuffix, referencesTarget, rejectParameters, rejectXMLValues, renameGeneratedResultNames, replaceOrForbidDefaults, returnsAtMostOneRow, setCandidateFinalCostEstimate, setCostEstimate, setCursorTargetTable, setInsertSource, setOptimizer, setReferencedTableMap, setResultColumns, setResultSetNumber, setResultToBooleanTrueNode, setScratchCostEstimate, setTableConstructorTypes, subqueryReferencesTarget, verifySelectStarSubquery
Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContext, getContextManager, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getLongProperty, getNullNode, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, getUDTDesc, isAtomic, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, 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, getOptimizerTracer, getReferencedTableMap, getResultSetNumber, optimizerTracingIsOn
Methods inherited from interface org.apache.derby.iapi.sql.compile.Visitable
accept, addTag, taggedWith
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Field Details
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cursorName
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preStmt
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exposedTableName
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baseTableName
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singleScanCostEstimate
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dummyTargetTable
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Constructor Details
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CurrentOfNode
CurrentOfNode(String correlationName, String cursor, Properties tableProperties, ContextManager cm)
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Method Details
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makeForMerge
static CurrentOfNode makeForMerge(String cursorName, FromBaseTable dummyTargetTable, ContextManager cm) Construct a dummy CurrentOfNode just for compiling the DELETE action of a MERGE statement.
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estimateCost
public CostEstimate estimateCost(OptimizablePredicateList predList, ConglomerateDescriptor cd, CostEstimate outerCost, Optimizer optimizer, RowOrdering rowOrdering) throws StandardException Description copied from interface:Optimizable
Estimate the cost of scanning this Optimizable using the given predicate list with the given conglomerate. It is assumed that the predicate list has already been classified. This cost estimate is just for one scan, not for the life of the query.- Specified by:
estimateCost
in interfaceOptimizable
- Overrides:
estimateCost
in classFromTable
- Parameters:
predList
- The predicate list to optimize againstcd
- The conglomerate descriptor to get the cost ofouterCost
- The estimated cost of the part of the plan outer to this optimizable.optimizer
- The optimizer to use to help estimate the costrowOrdering
- The row ordering for all the tables in the join order, including this one.- Returns:
- The estimated cost of doing the scan
- Throws:
StandardException
- Thrown on error- See Also:
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bindNonVTITables
ResultSetNode bindNonVTITables(DataDictionary dataDictionary, FromList fromListParam) throws StandardException Binding this FromTable means finding the prepared statement for the cursor and creating the result columns (the columns updatable on that cursor). We expect someone else to verify that the target table of the positioned update or delete is the table under this cursor.- Overrides:
bindNonVTITables
in classResultSetNode
- Parameters:
dataDictionary
- The DataDictionary to use for bindingfromListParam
- FromList to use/append to.- Returns:
- ResultSetNode Returns this.
- Throws:
StandardException
- Thrown on error
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bindExpressions
Bind the expressions in this ResultSetNode. This means binding the sub-expressions, as well as figuring out what the return type is for each expression.- Overrides:
bindExpressions
in classResultSetNode
- Parameters:
fromListParam
- FromList to use/append to.
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getMatchingColumn
Try to find a ResultColumn in the table represented by this CurrentOfNode that matches the name in the given ColumnReference.- Overrides:
getMatchingColumn
in classResultSetNode
- Parameters:
columnReference
- The columnReference whose name we're looking for in the given table.- Returns:
- A ResultColumn whose expression is the ColumnNode that matches the ColumnReference. Returns null if there is no match.
- Throws:
StandardException
- Thrown on error
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preprocess
ResultSetNode preprocess(int numTables, GroupByList gbl, FromList fromList) throws StandardException Preprocess a CurrentOfNode. For a CurrentOfNode, this simply means allocating a referenced table map to avoid downstream NullPointerExceptions. NOTE: There are no bits set in the referenced table map.- Overrides:
preprocess
in classResultSetNode
- Parameters:
numTables
- The number of tables in the DML Statementgbl
- The group by list, if anyfromList
- The from list, if any- Returns:
- ResultSetNode at top of preprocessed tree.
- Throws:
StandardException
- Thrown on error
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optimize
ResultSetNode optimize(DataDictionary dataDictionary, PredicateList predicateList, double outerRows) throws StandardException Optimize this CurrentOfNode. Nothing to do.- Overrides:
optimize
in classResultSetNode
- Parameters:
dataDictionary
- The DataDictionary to use for optimizationpredicateList
- The PredicateList to optimize. This should be a single-table predicate with the table the same as the table in this FromTable.outerRows
- The number of outer joining rows- Returns:
- ResultSetNode The top of the optimized subtree.
- Throws:
StandardException
- Thrown on error
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generate
Generation on a CurrentOfNode creates a scan on the cursor, CurrentOfResultSet.This routine will generate and return a call of the form:
ResultSetFactory.getCurrentOfResultSet(cursorName) - Overrides:
generate
in classQueryTreeNode
- Parameters:
acb
- The ActivationClassBuilder for the class being builtmb
- The execute() method to be built- Throws:
StandardException
- Thrown on error
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printSubNodes
void printSubNodes(int depth) Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.- Overrides:
printSubNodes
in classResultSetNode
- Parameters:
depth
- The depth of this node in the tree
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toString
Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing. -
getExposedName
String getExposedName()Description copied from class:FromTable
Get the exposed name for this table, which is the name that can be used to refer to it in the rest of the query.- Overrides:
getExposedName
in classFromTable
- Returns:
- The exposed name of this table.
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updateTargetLockMode
public int updateTargetLockMode()Get the lock mode for this table as the target of an update statement (a delete or update). This is implemented only for base tables and CurrentOfNodes.- Overrides:
updateTargetLockMode
in classResultSetNode
- Returns:
- The lock mode
- See Also:
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getExposedTableName
TableName getExposedTableName() -
getBaseCursorTargetTableName
TableName getBaseCursorTargetTableName() -
getCursorName
String getCursorName() -
getCursorStatement
ExecPreparedStatement getCursorStatement()Return the CursorNode associated with a positioned update/delete.- Returns:
- CursorNode The associated CursorNode.
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acceptChildren
Description copied from class:ResultSetNode
Accept the visitor for all visitable children of this node.- Overrides:
acceptChildren
in classFromTable
- Parameters:
v
- the visitor- Throws:
StandardException
- on error
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