org.apache.derby.impl.sql.compile

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:

Node, 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

Fields

Modifier and Type	Field and 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 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

Constructor Summary

Constructors

Constructor and Description
RowCountNode()

Method Summary

Methods

Modifier and Type	Method and Description
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, java.lang.Object hasJDBClimitClause) 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, 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, 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, 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, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, 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 .

hasJDBClimitClause

private boolean hasJDBClimitClause

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

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,
        java.lang.Object hasJDBClimitClause)
          throws StandardException

Initializer for a RowCountNode

Specified by:

init in interface Node

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