Class WindowFunctionNode

java.lang.Object

org.apache.derby.impl.sql.compile.QueryTreeNode

org.apache.derby.impl.sql.compile.ValueNode

org.apache.derby.impl.sql.compile.OperatorNode

org.apache.derby.impl.sql.compile.UnaryOperatorNode

org.apache.derby.impl.sql.compile.WindowFunctionNode

All Implemented Interfaces:

Visitable

Direct Known Subclasses:

AggregateWindowFunctionNode, RowNumberFunctionNode

public abstract class WindowFunctionNode
extends UnaryOperatorNode

Superclass of any window function call.

Field Summary

Fields

Modifier and Type	Field	Description
private ResultColumn	generatedRC
private ColumnReference	generatedRef
private WindowNode	window

Fields inherited from class UnaryOperatorNode

K_BASE, K_XMLPARSE, K_XMLSERIALIZE, kind, methodName, operand, operator, receiverInterfaceType, resultInterfaceType, UnaryArgTypes, UnaryMethodNames, UnaryOperators, UnaryResultTypes

Fields inherited from class ValueNode

transformed

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
WindowFunctionNode(ValueNode op, String functionName, WindowNode w, ContextManager cm)

Method Summary

Modifier and Type	Method	Description
(package private) ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates)	ValueNode override.
(package private) boolean	constantExpression(PredicateList whereClause)	ValueNode override.
private WindowDefinitionNode	definedWindow(WindowList windows, String name)
(package private) ColumnReference	getGeneratedRef()	Get the generated ColumnReference to this window function after the parent called replaceCallsWithColumnReferences().
(package private) ValueNode	getNewNullResultExpression()	Get the null result expression column.
(package private) WindowNode	getWindow()
boolean	isConstantExpression()	ValueNode override.
void	printSubNodes(int depth)	QueryTreeNode override.
(package private) ValueNode	replaceCallsWithColumnReferences(ResultColumnList rcl, int tableNumber)	Replace window function calls in the expression tree with a ColumnReference to that window function, append the aggregate to the supplied RCL (assumed to be from the child ResultSetNode) and return the ColumnReference.
(package private) void	setWindow(WindowDefinitionNode wdn)	Set window associated with this window function call.

Methods inherited from class UnaryOperatorNode

acceptChildren, addXmlOpMethodParams, bindOperand, bindParameter, categorize, generateExpression, getOperand, getOperatorString, getOrderableVariantType, getParameterOperand, getReceiverInterfaceName, isEquivalent, isSameNodeKind, preprocess, remapColumnReferencesToExpressions, setMethodName, setOperator, toString

Methods inherited from class OperatorNode

pushSqlXmlUtil

Methods inherited from class ValueNode

bindExpression, changeToCNF, checkIsBoolean, checkTopPredicatesForEqualsConditions, copyFields, eliminateNots, evaluateConstantExpressions, genEqualsFalseTree, generate, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isInListProbeNode, isParameterNode, isRelationalOperator, optimizableEqualityNode, putAndsOnTop, requiresTypeFromContext, selectivity, setCollationInfo, setCollationInfo, setCollationUsingCompilationSchema, setCollationUsingCompilationSchema, setNullability, setTransformed, setType, setType, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

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, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class Object

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

Field Details

window

private WindowNode window

generatedRC

private ResultColumn generatedRC

generatedRef

private ColumnReference generatedRef

Constructor Details

WindowFunctionNode

WindowFunctionNode(ValueNode op,
 String functionName,
 WindowNode w,
 ContextManager cm)
            throws StandardException

Parameters:

op - operand (null for now)

functionName - operator

w - window node (definition or reference)

cm - context manager

Throws:

StandardException

Method Details

isConstantExpression

public boolean isConstantExpression()

ValueNode override.

Overrides:

isConstantExpression in class UnaryOperatorNode

Returns:

Whether or not this expression tree represents a constant expression.

See Also:

• ValueNode.isConstantExpression()

constantExpression

boolean constantExpression(PredicateList whereClause)

ValueNode override.

Overrides:

constantExpression in class UnaryOperatorNode

Returns:

True means this expression tree represents a constant value.

See Also:

• ValueNode.isConstantExpression()

getWindow

WindowNode getWindow()

Returns:

window associated with this window function

setWindow

void setWindow(WindowDefinitionNode wdn)

Set window associated with this window function call.

Parameters:

wdn - window definition

bindExpression

ValueNode bindExpression(FromList fromList,
 SubqueryList subqueryList,
 List<AggregateNode> aggregates)
                  throws StandardException

ValueNode override.

Overrides:

bindExpression in class UnaryOperatorNode

Parameters:

fromList - The FROM list for the query this expression is in, for binding columns.

subqueryList - The subquery list being built as we find SubqueryNodes

aggregates - The aggregate list being built as we find AggregateNodes

Returns:

The new top of the expression tree.

Throws:

StandardException - Thrown on error

See Also:

• ValueNode.bindExpression(FromList, SubqueryList, List)

definedWindow

private WindowDefinitionNode definedWindow(WindowList windows,
 String name)

Returns:

if name matches a defined window (in windows), return the definition of that window, else null.

printSubNodes

public void printSubNodes(int depth)

QueryTreeNode override.

Overrides:

printSubNodes in class UnaryOperatorNode

Parameters:

depth - The depth of this node in the tree

See Also:

• QueryTreeNode.printSubNodes(int)

replaceCallsWithColumnReferences

ValueNode replaceCallsWithColumnReferences(ResultColumnList rcl,
 int tableNumber)
                                    throws StandardException

Replace window function calls in the expression tree with a ColumnReference to that window function, append the aggregate to the supplied RCL (assumed to be from the child ResultSetNode) and return the ColumnReference.

Parameters:

rcl - The RCL to append to.

tableNumber - The tableNumber for the new ColumnReference

Returns:

ValueNode The (potentially) modified tree.

Throws:

StandardException - Thrown on error

getGeneratedRef

ColumnReference getGeneratedRef()

Get the generated ColumnReference to this window function after the parent called replaceCallsWithColumnReferences().

There are cases where this will not have been done because the tree has been re-written to eliminate the window function, e.g. for this query:

    SELECT * FROM t WHERE EXISTS
          (SELECT ROW_NUMBER() OVER () FROM t)

in which case the top PRN of the subquery sitting over a WindowResultSetNode just contains a RC which is boolean constant true. This means that the replaceCallsWithColumnReferences will not have been called for this, so the returned generatedRef is null.

Returns:

the column reference

getNewNullResultExpression

ValueNode getNewNullResultExpression()
                              throws StandardException

Get the null result expression column.

Returns:

the value node

Throws:

StandardException - on error