org.h2.expression.condition

Class NullPredicate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.condition.SimplePredicate

org.h2.expression.condition.NullPredicate

public class NullPredicate
extends SimplePredicate

Null predicate (IS [NOT] NULL).

Field Summary

Fields inherited from class org.h2.expression.Expression

MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL

Constructor Summary

Constructors

Constructor and Description
NullPredicate(Expression left, boolean not)

Method Summary

Methods

Modifier and Type	Method and Description
void	createIndexConditions(Session session, TableFilter filter) Create index conditions if possible and attach them to the table filter.
Expression	getNotIfPossible(Session session) If it is possible, return the negated expression.
java.lang.StringBuilder	getSQL(java.lang.StringBuilder builder, boolean alwaysQuote) Appends the SQL statement of this expression to the specified builder.
TypeInfo	getType() Returns the data type.
Value	getValue(Session session) Return the resulting value for the current row.
Expression	optimize(Session session) Try to optimize the expression.

Methods inherited from class org.h2.expression.condition.SimplePredicate

getCost, getSubexpression, getSubexpressionCount, isEverything, mapColumns, setEvaluatable, updateAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, getAlias, getBooleanValue, getColumnName, getExpressionColumns, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNullable, getSchemaName, getSQL, getTableAlias, getTableName, getUnenclosedSQL, isAutoIncrement, isConstant, isNullConstant, isValueSet, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Constructor Detail

NullPredicate

public NullPredicate(Expression left,
             boolean not)

Method Detail

getSQL

public java.lang.StringBuilder getSQL(java.lang.StringBuilder builder,
                             boolean alwaysQuote)

Description copied from class: Expression

Appends the SQL statement of this expression to the specified builder. This may not always be the original SQL statement, specially after optimization.

Specified by:

getSQL in class Expression

Parameters:

builder - string builder

alwaysQuote - quote all identifiers

Returns:

the specified string builder

optimize

public Expression optimize(Session session)

Description copied from class: Expression

Try to optimize the expression.

Overrides:

optimize in class SimplePredicate

Parameters:

session - the session

Returns:

the optimized expression

getValue

public Value getValue(Session session)

Description copied from class: Expression

Return the resulting value for the current row.

Specified by:

getValue in class Expression

Parameters:

session - the session

Returns:

the result

getNotIfPossible

public Expression getNotIfPossible(Session session)

Description copied from class: Expression

If it is possible, return the negated expression. This is used to optimize NOT expressions: NOT ID>10 can be converted to ID<=10. Returns null if negating is not possible.

Overrides:

getNotIfPossible in class Expression

Parameters:

session - the session

Returns:

the negated expression, or null

createIndexConditions

public void createIndexConditions(Session session,
                         TableFilter filter)

Description copied from class: Expression

Create index conditions if possible and attach them to the table filter.

Overrides:

createIndexConditions in class Expression

Parameters:

session - the session

filter - the table filter

getType

public TypeInfo getType()

Description copied from class: Expression

Returns the data type. The data type may not be known before the optimization phase.

Specified by:

getType in class Expression

Returns:

the data type