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.UnaryComparisonOperatorNode
        
        org.apache.derby.impl.sql.compile.IsNullNode

All Implemented Interfaces:

Visitable, RelationalOperator
```
public final class IsNullNode
extends UnaryComparisonOperatorNode
implements RelationalOperator
```
This node represents either a unary IS NULL or IS NOT NULL comparison operator

Field Summary

Fields
Modifier and Type Field Description

private boolean notNull
If true, this node represents a NOT NULL node rather than a NULL node.

private DataValueDescriptor nullValue
- Fields inherited from class org.apache.derby.impl.sql.compile.UnaryOperatorNode
  K_BASE, K_XMLPARSE, K_XMLSERIALIZE, kind, methodName, operand, operator, receiverInterfaceType, resultInterfaceType, UnaryArgTypes, UnaryMethodNames, UnaryOperators, UnaryResultTypes
- 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_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX
- Fields inherited from interface org.apache.derby.impl.sql.compile.RelationalOperator
  EQUALS_RELOP, GREATER_EQUALS_RELOP, GREATER_THAN_RELOP, IS_NOT_NULL_RELOP, IS_NULL_RELOP, LESS_EQUALS_RELOP, LESS_THAN_RELOP, NOT_EQUALS_RELOP

Constructor Summary

Constructors
Constructor Description

IsNullNode(ValueNode operand, boolean notNull, ContextManager cm)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`(package private) void`	`bindParameter()`	Bind a ?
`boolean`	`compareWithKnownConstant(Optimizable optTable, boolean considerParameters)`	Return whether this operator compares the given Optimizable with a constant whose value is known at compile time.
`boolean`	`equalsComparisonWithConstantExpression(Optimizable optTable)`	Return whether this operator is an equality comparison of the given optimizable with a constant expression.
`void`	`generateNegate(MethodBuilder mb, Optimizable optTable)`	Generate an expression that evaluates to true if the result of the comparison should be negated.
`void`	`generateOperator(MethodBuilder mb, Optimizable optTable)`	Generate the comparison operator for this RelationalOperator.
`DataValueDescriptor`	`getCompareValue(Optimizable optTable)`	Return an Object representing the known value that this relational operator is comparing to a column in the given Optimizable.
`(package private) UnaryOperatorNode`	`getNegation(ValueNode operand)`	Negate the comparison.
`int`	`getOperator()`	Return the operator (as an int) for this RelationalOperator.
`(package private) java.lang.String`	`getReceiverInterfaceName()`	null operators are defined on DataValueDescriptor.
`int`	`getStartOperator(Optimizable optTable)`	Get the start operator for a scan (at the store level) for this RelationalOperator.
`int`	`getStopOperator(Optimizable optTable)`	Get the stop operator for a scan (at the store level) for this RelationalOperator.
`RelationalOperator`	`getTransitiveSearchClause(ColumnReference otherCR)`	Return a relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.
`(package private) boolean`	`isNullNode()`
`(package private) boolean`	`isRelationalOperator()`	Returns true if this ValueNode is a relational operator.
`(package private) boolean`	`optimizableEqualityNode(Optimizable optTable, int columnNumber, boolean isNullOkay)`	Return true if the predicate represents an optimizable equality node.
`double`	`selectivity(Optimizable optTable)`	The default selectivity for value nodes is 50%.
`private void`	`updateOperatorDetails()`
`boolean`	`usefulStartKey(Optimizable optTable)`	Tell whether this relop is a useful start key for the given table.
`boolean`	`usefulStopKey(Optimizable optTable)`	Tell whether this relop is a useful stop key for the given table.

Methods inherited from class org.apache.derby.impl.sql.compile.UnaryComparisonOperatorNode
bindComparisonOperator, bindExpression, eliminateNots, generateAbsoluteColumnId, generateExpressionOperand, generateOrderedNulls, generateQualMethod, generateRelativeColumnId, getColumnOperand, getColumnOperand, getExpressionOperand, getOperand, getOrderableVariantType, isQualifier, orderedNulls, selfComparison

Methods inherited from class org.apache.derby.impl.sql.compile.UnaryOperatorNode
acceptChildren, addXmlOpMethodParams, bindOperand, categorize, constantExpression, generateExpression, getOperand, getOperatorString, getOrderableVariantType, getParameterOperand, isConstantExpression, isEquivalent, isSameNodeKind, preprocess, printSubNodes, 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, evaluateConstantExpressions, genEqualsFalseTree, generate, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isInListProbeNode, isParameterNode, putAndsOnTop, requiresTypeFromContext, 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, 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 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.derby.impl.sql.compile.RelationalOperator
generateAbsoluteColumnId, generateExpressionOperand, generateOrderedNulls, generateQualMethod, generateRelativeColumnId, getColumnOperand, getColumnOperand, getExpressionOperand, getOperand, getOrderableVariantType, isQualifier, orderedNulls, selfComparison

- Field Detail
  - nullValue
```
private DataValueDescriptor nullValue
```
  - notNull
```
private boolean notNull
```
    If true, this node represents a NOT NULL node rather than a NULL node. Note that this state is mutable, cf getNegation(org.apache.derby.impl.sql.compile.ValueNode).
- Constructor Detail
  - IsNullNode
```
IsNullNode(ValueNode operand,
           boolean notNull,
           ContextManager cm)
    throws StandardException
```
    Throws:
    
    StandardException
- Method Detail
  - updateOperatorDetails
```
private void updateOperatorDetails()
```
  - getNegation
```
UnaryOperatorNode getNegation(ValueNode operand)
                       throws StandardException
```
    Negate the comparison.
    
    Specified by:
    
    getNegation in class UnaryComparisonOperatorNode
    
    Parameters:
    
    operand - The operand of the operator
    
    Returns:
    
    UnaryOperatorNode The negated expression
    
    Throws:
    
    StandardException - Thrown on error
  - bindParameter
```
void bindParameter()
            throws StandardException
```
    Bind a ? parameter operand of the IS [NOT] NULL predicate.
    
    Overrides:
    
    bindParameter in class UnaryOperatorNode
    
    Throws:
    
    StandardException - Thrown on error
  - usefulStartKey
```
public boolean usefulStartKey(Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Tell whether this relop is a useful start key for the given table. It has already been determined that the relop has a column from the given table on one side or the other.
    
    Specified by:
    
    usefulStartKey in interface RelationalOperator
    
    Parameters:
    
    optTable - The Optimizable table for which we want to know whether this is a useful start key.
    
    Returns:
    
    true if this is a useful start key
    
    See Also:
    
    RelationalOperator.usefulStartKey(org.apache.derby.iapi.sql.compile.Optimizable)
  - usefulStopKey
```
public boolean usefulStopKey(Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Tell whether this relop is a useful stop key for the given table. It has already been determined that the relop has a column from the given table on one side or the other.
    
    Specified by:
    
    usefulStopKey in interface RelationalOperator
    
    Parameters:
    
    optTable - The Optimizable table for which we want to know whether this is a useful stop key.
    
    Returns:
    
    true if this is a useful stop key
    
    See Also:
    
    RelationalOperator.usefulStopKey(org.apache.derby.iapi.sql.compile.Optimizable)
  - getStartOperator
```
public int getStartOperator(Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Get the start operator for a scan (at the store level) for this RelationalOperator.
    
    Specified by:
    
    getStartOperator in interface RelationalOperator
    
    Overrides:
    
    getStartOperator in class UnaryComparisonOperatorNode
    
    Parameters:
    
    optTable - The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on.
    
    Returns:
    
    Either ScanController.GT or ScanController.GE
    
    See Also:
    
    RelationalOperator.getStartOperator(org.apache.derby.iapi.sql.compile.Optimizable)
  - getStopOperator
```
public int getStopOperator(Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Get the stop operator for a scan (at the store level) for this RelationalOperator.
    
    Specified by:
    
    getStopOperator in interface RelationalOperator
    
    Overrides:
    
    getStopOperator in class UnaryComparisonOperatorNode
    
    Parameters:
    
    optTable - The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on.
    
    Returns:
    
    Either ScanController.GT or ScanController.GE
    
    See Also:
    
    RelationalOperator.getStopOperator(org.apache.derby.iapi.sql.compile.Optimizable)
  - generateOperator
```
public void generateOperator(MethodBuilder mb,
                             Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Generate the comparison operator for this RelationalOperator. The operator can depend on which side of this operator the optimizable column is.
    
    Specified by:
    
    generateOperator in interface RelationalOperator
    
    Parameters:
    
    mb - The method the generated code is to go into
    
    optTable - The optimizable table we're doing the scan on.
    
    See Also:
    
    RelationalOperator.generateOperator(org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable)
  - generateNegate
```
public void generateNegate(MethodBuilder mb,
                           Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Generate an expression that evaluates to true if the result of the comparison should be negated. For example, col > 1 generates a comparison operator of <= and a negation of true, while col < 1 generates a comparison operator of < and a negation of false.
    
    Specified by:
    
    generateNegate in interface RelationalOperator
    
    Parameters:
    
    mb - The method the generated code is to go into
    
    optTable - The Optimizable table the Qualifier will qualify
    
    See Also:
    
    RelationalOperator.generateNegate(org.apache.derby.iapi.services.compiler.MethodBuilder, org.apache.derby.iapi.sql.compile.Optimizable)
  - getOperator
```
public int getOperator()
```
    Description copied from interface: RelationalOperator
    
    Return the operator (as an int) for this RelationalOperator.
    
    Specified by:
    
    getOperator in interface RelationalOperator
    
    Returns:
    
    int The operator for this RelationalOperator.
    
    See Also:
    
    RelationalOperator.getOperator()
  - compareWithKnownConstant
```
public boolean compareWithKnownConstant(Optimizable optTable,
                                        boolean considerParameters)
```
    Description copied from interface: RelationalOperator
    
    Return whether this operator compares the given Optimizable with a constant whose value is known at compile time.
    
    Specified by:
    
    compareWithKnownConstant in interface RelationalOperator
    
    See Also:
    
    RelationalOperator.compareWithKnownConstant(org.apache.derby.iapi.sql.compile.Optimizable, boolean)
  - getCompareValue
```
public DataValueDescriptor getCompareValue(Optimizable optTable)
                                    throws StandardException
```
    Description copied from interface: RelationalOperator
    
    Return an Object representing the known value that this relational operator is comparing to a column in the given Optimizable.
    
    Specified by:
    
    getCompareValue in interface RelationalOperator
    
    Throws:
    
    StandardException - Thrown on error
    
    See Also:
    
    RelationalOperator.getCompareValue(org.apache.derby.iapi.sql.compile.Optimizable)
  - equalsComparisonWithConstantExpression
```
public boolean equalsComparisonWithConstantExpression(Optimizable optTable)
```
    Description copied from interface: RelationalOperator
    
    Return whether this operator is an equality comparison of the given optimizable with a constant expression.
    
    Specified by:
    
    equalsComparisonWithConstantExpression in interface RelationalOperator
    
    See Also:
    
    RelationalOperator.equalsComparisonWithConstantExpression(org.apache.derby.iapi.sql.compile.Optimizable)
  - getTransitiveSearchClause
```
public RelationalOperator getTransitiveSearchClause(ColumnReference otherCR)
                                             throws StandardException
```
    Description copied from interface: RelationalOperator
    
    Return a relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.
    
    Specified by:
    
    getTransitiveSearchClause in interface RelationalOperator
    
    Parameters:
    
    otherCR - The ColumnReference for the new (left) operand.
    
    Returns:
    
    A relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.
    
    Throws:
    
    StandardException - thrown on error
    
    See Also:
    
    RelationalOperator.getTransitiveSearchClause(org.apache.derby.impl.sql.compile.ColumnReference)
  - getReceiverInterfaceName
```
java.lang.String getReceiverInterfaceName()
```
    null operators are defined on DataValueDescriptor. Overrides method in UnaryOperatorNode for code generation purposes.
    
    Overrides:
    
    getReceiverInterfaceName in class UnaryOperatorNode
  - selectivity
```
public double selectivity(Optimizable optTable)
```
    Description copied from class: ValueNode
    
    The default selectivity for value nodes is 50%. This is overridden in specific cases, such as the RelationalOperators.
    
    Overrides:
    
    selectivity in class ValueNode
  - isNullNode
```
boolean isNullNode()
```
  - isRelationalOperator
```
boolean isRelationalOperator()
```
    Description copied from class: ValueNode
    
    Returns true if this ValueNode is a relational operator. Relational Operators are <, <=, =, >, >=, <> as well as IS NULL and IS NOT NULL. This is the preferred way of figuring out if a ValueNode is relational or not.
    
    Overrides:
    
    isRelationalOperator in class ValueNode
    
    See Also:
    
    ValueNode.isRelationalOperator()
  - optimizableEqualityNode
```
boolean optimizableEqualityNode(Optimizable optTable,
                                int columnNumber,
                                boolean isNullOkay)
```
    Description copied from class: ValueNode
    Return true if the predicate represents an optimizable equality node. an expression is considered to be an optimizable equality node if all the following conditions are met:
    
    the operator is an = or IS NULL operator
    
    one of the operands is a column specified by optTable/columnNumber
    
    Both operands are not the same column; i.e tab.col = tab.col
    
    There are no implicit varchar comparisons of the operands; i.e either both operands are string like (varchar, char, longvarchar) or neither operand is string like
    Overrides:
    
    optimizableEqualityNode in class ValueNode
    
    Parameters:
    
    optTable - the table being optimized. Column reference must be from this table.
    
    columnNumber - the column number. One of the operands of this predicate must be the column number specified by optTable/columnNumber
    
    isNullOkay - if set to true we also consider IS NULL predicates; otherwise consider only = predicates.
    
    See Also:
    
    ValueNode.optimizableEqualityNode(org.apache.derby.iapi.sql.compile.Optimizable, int, boolean)

Modifier and Type	Field	Description
`private boolean`	`notNull`	If `true`, this node represents a NOT NULL node rather than a NULL node.
`private DataValueDescriptor`	`nullValue`

Class IsNullNode

Field Summary

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

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

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

Fields inherited from interface org.apache.derby.impl.sql.compile.RelationalOperator

Constructor Summary

Method Summary

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

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

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

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

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

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.derby.impl.sql.compile.RelationalOperator

Field Detail

nullValue

notNull

Constructor Detail

IsNullNode

Method Detail

updateOperatorDetails

getNegation

bindParameter

usefulStartKey

usefulStopKey

getStartOperator

getStopOperator

generateOperator

generateNegate

getOperator

compareWithKnownConstant

getCompareValue

equalsComparisonWithConstantExpression

getTransitiveSearchClause

getReceiverInterfaceName

selectivity

isNullNode

isRelationalOperator

optimizableEqualityNode