Class RowCountNode

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.SingleChildResultSetNode

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.

Nested Class Summary

Nested classes/interfaces inherited from class ResultSetNode

ResultSetNode.QueryExpressionClauses

Field Summary

Fields

Modifier and Type	Field	Description
private ValueNode	fetchFirst	If not null, this represents the value of a .
private boolean	hasJDBClimitClause	True if the offset/fetchFirst clauses were added by JDBC LIMIT syntax.
private ValueNode	offset	If not null, this represents the value of a .

Fields inherited from class SingleChildResultSetNode

childResult, hasTrulyTheBestAccessPath

Fields inherited from class 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 QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor	Description
RowCountNode(ResultSetNode childResult, ResultColumnList rcl, ValueNode offset, ValueNode fetchFirst, boolean hasJDBClimitClause, ContextManager cm)	Constructor for a RowCountNode

Method Summary

Modifier and Type	Method	Description
(package private) void	generate(ActivationClassBuilder acb, MethodBuilder mb)	Generate code.
private void	generateExprFun(ExpressionClassBuilder ecb, MethodBuilder mb, ValueNode vn)
String	toString()	Convert this object to a String.

Methods inherited from class SingleChildResultSetNode

acceptChildren, addNewPredicate, adjustForSortElimination, adjustForSortElimination, changeAccessPath, decrementLevel, ensurePredicateList, flattenableInFromSubquery, forUpdate, getChildResult, getFinalCostEstimate, getFromTableByName, getTrulyTheBestAccessPath, initAccessPaths, isNotExists, isOneRowResultSet, isOrderedOn, modifyAccessPaths, optimize, preprocess, printSubNodes, pullOptPredicates, pushExpressions, referencesSessionSchema, referencesTarget, reflectionNeededForProjection, setChildResult, setLevel, subqueryReferencesTarget, updateBestPlanMap, updateTargetLockMode

Methods inherited from class FromTable

assignCostEstimate, canBeOrdered, columnsAreUpdatable, considerSortAvoidancePath, convertAbsoluteToRelativeColumnPosition, cursorTargetTable, estimateCost, feasibleJoinStrategy, fillInReferencedTableMap, flatten, getBaseTableName, getBestAccessPath, getBestSortAvoidancePath, getCorrelationName, getCostEstimate, getCurrentAccessPath, getExposedName, getLevel, getMergeTableID, getName, getNumColumnsReturned, getOrigTableName, getProperties, getResultColumnsForList, getSchemaDescriptor, getSchemaDescriptor, getScratchCostEstimate, getTableDescriptor, getTableName, getTableNumber, getUserSpecifiedJoinStrategy, hashKeyColumns, hasLargeObjectColumns, hasTableNumber, initialCapacity, isBaseTable, isCoveringIndex, isFlattenableJoinNode, isJoinColumnForRightOuterJoin, isMaterializable, isOneRowScan, isTargetTable, legalJoinOrder, loadFactor, LOJ_reorderable, markUpdatableByCursor, maxCapacity, memoryUsageOK, modifyAccessPath, needsSpecialRCLBinding, nextAccessPath, optimizeIt, optimizeSubqueries, pushOptPredicate, rememberAsBest, rememberJoinStrategyAsBest, rememberSortAvoidancePath, resetJoinStrategies, setCostEstimateCost, setHashKeyColumns, setMergeTableID, setOrigTableName, setProperties, setTableNumber, startOptimizing, supportsMultipleInstantiations, tellRowOrderingAboutConstantColumns, transformOuterJoins, uniqueJoin, verifyProperties

Methods inherited from class ResultSetNode

assignResultSetNumber, bindExpressions, bindExpressionsWithTables, bindNonVTITables, bindResultColumns, bindResultColumns, bindTargetExpressions, bindUntypedNullsToResultColumns, bindVTITables, columnTypesAndLengthsMatch, considerMaterialization, enhanceRCLForInsert, generateNormalizationResultSet, generateResultSet, genProjectRestrict, genProjectRestrict, genProjectRestrictForReordering, getAllResultColumns, getCandidateFinalCostEstimate, getCostEstimate, getCursorTargetTable, getFromList, getMatchingColumn, getNewCostEstimate, getOptimizer, getOptimizerImpl, getRCLForInsert, getReferencedTableMap, getResultColumns, getResultSetNumber, getScratchCostEstimate, isCursorTargetTable, isInsertSource, isPossibleDistinctScan, isStatementResultSet, isUpdatableCursor, LOJgetReferencedTables, makeResultDescription, makeResultDescriptors, markAsCursorTargetTable, markForDistinctScan, markStatementResultSet, modifyAccessPaths, notCursorTargetTable, notFlattenableJoin, numDistinctAggregates, parseDefault, performMaterialization, printQueryExpressionSuffixClauses, projectResultColumns, pushOffsetFetchFirst, pushOrderByList, pushQueryExpressionSuffix, rejectParameters, rejectXMLValues, renameGeneratedResultNames, replaceOrForbidDefaults, returnsAtMostOneRow, setCandidateFinalCostEstimate, setCostEstimate, setCursorTargetTable, setInsertSource, setOptimizer, setReferencedTableMap, setResultColumns, setResultSetNumber, setResultToBooleanTrueNode, setScratchCostEstimate, setTableConstructorTypes, verifySelectStarSubquery

Methods inherited from class 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, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class Object

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

Methods inherited from interface Optimizable

getDataDictionary, getOptimizerTracer, getReferencedTableMap, getResultSetNumber, optimizerTracingIsOn

Methods inherited from interface Visitable

accept, addTag, taggedWith

Field Details

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 .

hasJDBClimitClause

private boolean hasJDBClimitClause

True if the offset/fetchFirst clauses were added by JDBC LIMIT syntax.

Constructor Details

RowCountNode

RowCountNode(ResultSetNode childResult,
 ResultColumnList rcl,
 ValueNode offset,
 ValueNode fetchFirst,
 boolean hasJDBClimitClause,
 ContextManager cm)
      throws StandardException

Constructor for a RowCountNode

Parameters:

childResult - The result set for which we want to get only a subset

rcl - The result columns we want

offset - The offset, if any, in the result set

fetchFirst - The number of rows to inspect to get

hasJDBClimitClause - true if a JDBC limit syntax was used

cm - The context manager

Throws:

StandardException

Method Details

generate

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 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