org.h2.expression

Class Parameter

java.lang.Object

org.h2.expression.Expression

org.h2.expression.Parameter

All Implemented Interfaces:

ParameterInterface

public class Parameter
extends Expression
implements ParameterInterface

A parameter of a prepared statement.

Field Summary

Fields inherited from class org.h2.expression.Expression

MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL

Constructor Summary

Constructors

Constructor and Description
Parameter(int index)

Method Summary

Methods

Modifier and Type	Method and Description
void	checkSet() Check if the value is set.
int	getCost() Estimate the cost to process the expression.
int	getIndex()
Expression	getNotIfPossible(Session session) If it is possible, return the negated expression.
Value	getParamValue() Get the value of the parameter if set.
long	getPrecision() Get the expected precision of this parameter.
int	getScale() Get the expected scale of this parameter.
java.lang.StringBuilder	getSQL(java.lang.StringBuilder builder) 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.
int	getValueType() Get the expected data type of the parameter if no value is set, or the data type of the value if one is set.
boolean	isConstant() Check if this expression will always return the same value.
boolean	isEverything(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.
boolean	isValueSet() Is the value of a parameter set.
void	mapColumns(ColumnResolver resolver, int level, int state) Map the columns of the resolver to expression columns.
Expression	optimize(Session session) Try to optimize the expression.
void	setColumn(Column column)
void	setEvaluatable(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.
void	setValue(Value v)
void	setValue(Value v, boolean closeOld) Set the value of the parameter.
void	updateAggregate(Session session, int stage) Update an aggregate value.

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getExpressionColumns, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNullable, getSchemaName, getSQL, getSubexpression, getSubexpressionCount, getTableAlias, getTableName, getUnenclosedSQL, isAutoIncrement, isGeneratedKey, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.expression.ParameterInterface

getNullable

Constructor Detail

Parameter

public Parameter(int index)

Method Detail

getSQL

public java.lang.StringBuilder getSQL(java.lang.StringBuilder builder)

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

Returns:

the specified string builder

setValue

public void setValue(Value v,
            boolean closeOld)

Description copied from interface: ParameterInterface

Set the value of the parameter.

Specified by:

setValue in interface ParameterInterface

Parameters:

v - the new value

closeOld - if the old value (if one is set) should be closed

setValue

public void setValue(Value v)

getParamValue

public Value getParamValue()

Description copied from interface: ParameterInterface

Get the value of the parameter if set.

Specified by:

getParamValue in interface ParameterInterface

Returns:

the value or null

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

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

getValueType

public int getValueType()

Description copied from interface: ParameterInterface

Get the expected data type of the parameter if no value is set, or the data type of the value if one is set.

Specified by:

getValueType in interface ParameterInterface

Returns:

the data type

mapColumns

public void mapColumns(ColumnResolver resolver,
              int level,
              int state)

Description copied from class: Expression

Map the columns of the resolver to expression columns.

Specified by:

mapColumns in class Expression

Parameters:

resolver - the column resolver

level - the subquery nesting level

state - current state for nesting checks, initial value is Expression.MAP_INITIAL

checkSet

public void checkSet()

Description copied from interface: ParameterInterface

Check if the value is set.

Specified by:

checkSet in interface ParameterInterface

optimize

public Expression optimize(Session session)

Description copied from class: Expression

Try to optimize the expression.

Specified by:

optimize in class Expression

Parameters:

session - the session

Returns:

the optimized expression

isConstant

public boolean isConstant()

Description copied from class: Expression

Check if this expression will always return the same value.

Overrides:

isConstant in class Expression

Returns:

if the expression is constant

isValueSet

public boolean isValueSet()

Description copied from class: Expression

Is the value of a parameter set.

Specified by:

isValueSet in interface ParameterInterface

Overrides:

isValueSet in class Expression

Returns:

true if set

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                  boolean b)

Description copied from class: Expression

Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.

Specified by:

setEvaluatable in class Expression

Parameters:

tableFilter - the table filter

b - true if the table filter can return value

getScale

public int getScale()

Description copied from interface: ParameterInterface

Get the expected scale of this parameter.

Specified by:

getScale in interface ParameterInterface

Returns:

the expected scale

getPrecision

public long getPrecision()

Description copied from interface: ParameterInterface

Get the expected precision of this parameter.

Specified by:

getPrecision in interface ParameterInterface

Returns:

the expected precision

updateAggregate

public void updateAggregate(Session session,
                   int stage)

Description copied from class: Expression

Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.

Specified by:

updateAggregate in class Expression

Parameters:

session - the session

stage - select stage

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Specified by:

isEverything in class Expression

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

getCost

public int getCost()

Description copied from class: Expression

Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.

Specified by:

getCost in class Expression

Returns:

the estimated cost

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

setColumn

public void setColumn(Column column)

getIndex

public int getIndex()