org.apache.derby.impl.sql.compile
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:

Node, Visitable

Direct Known Subclasses:

AggregateWindowFunctionNode, RowNumberFunctionNode

public abstract class WindowFunctionNode
extends UnaryOperatorNode

Superclass of any window function call.

Field Summary

private ResultColumn	generatedRC
private ColumnReference	generatedRef
private WindowNode	window

Fields inherited from class org.apache.derby.impl.sql.compile.UnaryOperatorNode

methodName, operand, operator, receiverInterfaceType, resultInterfaceType, UnaryArgTypes, UnaryMethodNames, UnaryOperators, UnaryResultTypes, XMLPARSE_OP, XMLSERIALIZE_OP

Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode

transformed

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

WindowFunctionNode()

Method Summary

ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.List aggregateVector) ValueNode override.
boolean	constantExpression(PredicateList whereClause) ValueNode override.
private WindowDefinitionNode	definedWindow(WindowList windows, java.lang.String name)
ColumnReference	getGeneratedRef() Get the generated ColumnReference to this window function after the parent called replaceCallsWithColumnReferences().
ValueNode	getNewNullResultExpression() Get the null result expression column.
WindowNode	getWindow()
void	init(java.lang.Object arg1, java.lang.Object arg2, java.lang.Object arg3) Initializer for a WindowFunctionNode
boolean	isConstantExpression() ValueNode override.
void	printSubNodes(int depth) QueryTreeNode override.
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.
void	setWindow(WindowDefinitionNode wdn) Set window associated with this window function call.

Methods inherited from class org.apache.derby.impl.sql.compile.UnaryOperatorNode

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

Methods inherited from class org.apache.derby.impl.sql.compile.OperatorNode

pushSqlXmlUtil

Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode

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

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, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, referencesSessionSchema, 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

Field Detail

window

private WindowNode window

generatedRC

private ResultColumn generatedRC

generatedRef

private ColumnReference generatedRef

Constructor Detail

WindowFunctionNode

public WindowFunctionNode()

Method Detail

init

public void init(java.lang.Object arg1,
                 java.lang.Object arg2,
                 java.lang.Object arg3)

Initializer for a WindowFunctionNode

Specified by:

init in interface Node

Overrides:

init in class UnaryOperatorNode

Parameters:

arg1 - null (operand)

arg2 - function mame (operator)

arg3 - window node (definition or reference)

Throws:

StandardException

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

public 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

public WindowNode getWindow()

Returns:

window associated with this window function

setWindow

public void setWindow(WindowDefinitionNode wdn)

Set window associated with this window function call.

Parameters:

wdn - window definition

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.List aggregateVector)
                         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

aggregateVector - The aggregate vector being built as we find AggregateNodes

Returns:

The new top of the expression tree.

Throws:

StandardException - Thrown on error

See Also:

ValueNode.bindExpression(org.apache.derby.impl.sql.compile.FromList, org.apache.derby.impl.sql.compile.SubqueryList, java.util.List)

definedWindow

private WindowDefinitionNode definedWindow(WindowList windows,
                                           java.lang.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

public 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

public 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

public ValueNode getNewNullResultExpression()
                                     throws StandardException

Get the null result expression column.

Returns:

the value node

Throws:

StandardException - on error