org.apache.derby.impl.sql.compile

Class ValueNode

java.lang.Object

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

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

All Implemented Interfaces:

Visitable

Direct Known Subclasses:

BinaryArithmeticOperatorNode, BinaryComparisonOperatorNode, BinaryListOperatorNode, BooleanConstantNode, CharConstantNode, ColumnReference, DB2LengthOperatorNode, DefaultNode, LengthOperatorNode, LikeEscapeOperatorNode, NumericConstantNode, ParameterNode, UnaryComparisonOperatorNode, UnaryLogicalOperatorNode, UntypedNullConstantNode, VarbitConstantNode, WindowFunctionNode, XMLConstantNode

public abstract class ValueNode
extends QueryTreeNode

A ValueNode is an abstract class for all nodes that can represent data values, that is, constants, columns, and expressions.

Method Summary

Modifier and Type	Method and Description
ValueNode	checkIsBoolean() Bind time logic.
double	selectivity(Optimizable optTable) The default selectivity for value nodes is 50%.
void	setCollationInfo(DataTypeDescriptor collationInfoType) Set the collation type and derivation of this node based upon the collation information in the passed in type.
void	setCollationInfo(int collationType, int collationDerivation) Set the collation type and derivation of this node based upon the collation information passed in.
void	setNullability(boolean nullability) Set the nullability of this value.
java.lang.String	toString() Convert this object to a String.
boolean	updatableByCursor()

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

accept, addTag, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, createTypeDependency, getBeginOffset, getDataDictionary, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getUDTDesc, isAtomic, makeConstantAction, makeTableName, makeTableName, optimizerTracingIsOn, orReliability, referencesSessionSchema, setBeginOffset, setEndOffset, taggedWith, treePrint

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

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 QueryTreeNode

Returns:

This object as a String

setNullability

public void setNullability(boolean nullability)
                    throws StandardException

Set the nullability of this value.

Throws:

StandardException

setCollationInfo

public void setCollationInfo(DataTypeDescriptor collationInfoType)
                      throws StandardException

Set the collation type and derivation of this node based upon the collation information in the passed in type. Note that the base type of this node is not changed (e.g. INTEGER), only its collation settings. This may result in a different object being returned from getTypeServices().

Parameters:

collationInfoType - Type to take collation type and derivation from.

Throws:

StandardException - Error setting type.

setCollationInfo

public void setCollationInfo(int collationType,
                             int collationDerivation)
                      throws StandardException

Set the collation type and derivation of this node based upon the collation information passed in. This may result in a different object being returned from getTypeServices().

Parameters:

collationType - Collation type

collationDerivation - Collation derivation

Throws:

StandardException - Error setting type

updatableByCursor

public boolean updatableByCursor()

Returns:

the default updatability for an expression - false

checkIsBoolean

public ValueNode checkIsBoolean()
                         throws StandardException

Bind time logic. Raises an error if this ValueNode does not resolve to a boolean value. This method is called by WHERE clauses.

Returns:

bound coercion of this node to a builtin type as necessary

Throws:

StandardException - Thrown on error

selectivity

public double selectivity(Optimizable optTable)
                   throws StandardException

The default selectivity for value nodes is 50%. This is overridden in specific cases, such as the RelationalOperators.

Throws:

StandardException