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

java.lang.Object
  extended by org.apache.derby.impl.sql.compile.QueryTreeNode
      extended by org.apache.derby.impl.sql.compile.ResultSetNode
          extended by org.apache.derby.impl.sql.compile.FromTable
              extended by org.apache.derby.impl.sql.compile.SingleChildResultSetNode
                  extended by org.apache.derby.impl.sql.compile.RowCountNode
All Implemented Interfaces:
Optimizable, Visitable

public final class RowCountNode
extends SingleChildResultSetNode

The result set generated by this node (RowCountResultSet) implements the filtering of rows needed for the and the . It sits on top of the normal SELECT's top result set, but under any ScrollInsensitiveResultSet. The latter's positioning is needed for the correct functioning of and in the presence of scrollable and/or updatable result sets and CURRENT OF cursors.


Field Summary
private  ValueNode fetchFirst
          If not null, this represents the value of a .
private  ValueNode offset
          If not null, this represents the value of a .
 
Fields inherited from class org.apache.derby.impl.sql.compile.SingleChildResultSetNode
childResult, hasTrulyTheBestAccessPath
 
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.ResultSetNode
costEstimate, cursorTargetTable, finalCostEstimate, insertSource, optimizer, referencedTableMap, resultColumns, resultSetNumber, scratchCostEstimate, statementResultSet
 
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired
 
Constructor Summary
RowCountNode()
           
 
Method Summary
 void generate(ActivationClassBuilder acb, MethodBuilder mb)
          Generate code.
private  void generateExprFun(ExpressionClassBuilder ecb, MethodBuilder mb, ValueNode vn)
           
 void init(java.lang.Object childResult, java.lang.Object rcl, java.lang.Object offset, java.lang.Object fetchFirst)
          Initializer for a RowCountNode
 java.lang.String toString()
          Convert this object to a String.
 
Methods inherited from class org.apache.derby.impl.sql.compile.SingleChildResultSetNode
acceptChildren, addNewPredicate, adjustForSortElimination, adjustForSortElimination, changeAccessPath, decrementLevel, ensurePredicateList, flattenableInFromSubquery, forUpdate, getChildResult, getFinalCostEstimate, getFromTableByName, getTrulyTheBestAccessPath, init, initAccessPaths, isNotExists, isOneRowResultSet, isOrderedOn, modifyAccessPaths, optimize, preprocess, printSubNodes, pullOptPredicates, pushExpressions, referencesSessionSchema, referencesTarget, reflectionNeededForProjection, setChildResult, setLevel, subqueryReferencesTarget, updateBestPlanMap, updateTargetLockMode
 
Methods inherited from class org.apache.derby.impl.sql.compile.FromTable
assignCostEstimate, canBeOrdered, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, flatten, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCorrelationName, getCostEstimate, getCurrentAccessPath, getExposedName, getLevel, getName, getNumColumnsReturned, getOrigTableName, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getUserSpecifiedJoinStrategy, hashKeyColumns, hasTableNumber, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeIt, optimizeSubqueries, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setCostEstimate, setHashKeyColumns, setOrigTableName, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, transformOuterJoins, uniqueJoin, verifyProperties
 
Methods inherited from class org.apache.derby.impl.sql.compile.ResultSetNode
assignResultSetNumber, bindExpressions, bindExpressionsWithTables, bindNonVTITables, bindResultColumns, bindResultColumns, bindTargetExpressions, bindUntypedNullsToResultColumns, bindVTITables, columnTypesAndLengthsMatch, considerMaterialization, disablePrivilegeCollection, enhanceRCLForInsert, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCostEstimate, getCursorTargetTable, getFromList, getMatchingColumn, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, isPossibleDistinctScan, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, performMaterialization, projectResultColumns, pushOffsetFetchFirst, pushOrderByList, rejectParameters, rejectXMLValues, renameGeneratedResultNames, replaceOrForbidDefaults, returnsAtMostOneRow, setInsertSource, setReferencedTableMap, setResultColumns, setResultToBooleanTrueNode, setTableConstructorTypes, verifySelectStarSubquery
 
Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, bindOffsetFetch, bindRowMultiSet, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, formatNodeString, foundString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, stackPrint, 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

offset

private ValueNode offset
If not null, this represents the value of a .


fetchFirst

private ValueNode fetchFirst
If not null, this represents the value of a .

Constructor Detail

RowCountNode

public RowCountNode()
Method Detail

init

public void init(java.lang.Object childResult,
                 java.lang.Object rcl,
                 java.lang.Object offset,
                 java.lang.Object fetchFirst)
          throws StandardException
Initializer for a RowCountNode

Overrides:
init in class QueryTreeNode
Throws:
StandardException

generate

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

Overrides:
generate in class QueryTreeNode
Parameters:
acb - activation class builder
mb - method builder
Throws:
StandardException - Thrown on error

generateExprFun

private void generateExprFun(ExpressionClassBuilder ecb,
                             MethodBuilder mb,
                             ValueNode vn)
                      throws StandardException
Throws:
StandardException

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 FromTable
Returns:
This object as a String

Built on Thu 2011-03-10 11:54:14+0000, from revision ???

Apache Derby V10.6 Internals - Copyright © 2004,2007 The Apache Software Foundation. All Rights Reserved.