Package org.h2.expression.function

Class Function0_1

java.lang.Object

org.h2.expression.Expression

org.h2.expression.function.Function0_1

All Implemented Interfaces:

NamedExpression, HasSQL, Typed

Direct Known Subclasses:

RandFunction

public abstract class Function0_1
extends Expression
implements NamedExpression

Function with one optional argument.

Field Summary

Fields

Modifier and Type	Field	Description
protected Expression	arg	The argument of the operation.
protected TypeInfo	type	The type of the result.

Fields inherited from class org.h2.expression.Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

Fields inherited from interface org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Function0_1(Expression arg)

Method Summary

Modifier and Type	Method	Description
int	getCost()	Estimate the cost to process the expression.
Expression	getSubexpression(int index)	Returns subexpression with specified index.
int	getSubexpressionCount()	Returns count of subexpressions.
TypeInfo	getType()	Returns the data type.
StringBuilder	getUnenclosedSQL(StringBuilder builder, int sqlFlags)	Get the SQL statement of this expression.
boolean	isEverything(ExpressionVisitor visitor)	Check if this expression and all sub-expressions can fulfill a criteria.
void	mapColumns(ColumnResolver resolver, int level, int state)	Map the columns of the resolver to expression columns.
void	setEvaluatable(TableFilter tableFilter, boolean value)	Tell the expression columns whether the table filter can return values now.
void	updateAggregate(SessionLocal session, int stage)	Update an aggregate value.

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getTypeIfStaticallyKnown, getValue, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimize, optimizeCondition, 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.util.HasSQL

getTraceSQL

Methods inherited from interface org.h2.expression.function.NamedExpression

getName

Field Details

arg

protected Expression arg

The argument of the operation.

type

protected TypeInfo type

The type of the result.

Constructor Details

Function0_1

protected Function0_1(Expression arg)

Method Details

getType

public TypeInfo getType()

Description copied from class: Expression

Returns the data type. The data type may be unknown before the optimization phase.

Specified by:

getType in interface Typed

Specified by:

getType in class Expression

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

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
 boolean value)

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

value - true if the table filter can return value

updateAggregate

public void updateAggregate(SessionLocal 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

getSubexpressionCount

public int getSubexpressionCount()

Description copied from class: Expression

Returns count of subexpressions.

Overrides:

getSubexpressionCount in class Expression

Returns:

count of subexpressions

getSubexpression

public Expression getSubexpression(int index)

Description copied from class: Expression

Returns subexpression with specified index.

Overrides:

getSubexpression in class Expression

Parameters:

index - 0-based index

Returns:

subexpression with specified index, may be null

getUnenclosedSQL

public StringBuilder getUnenclosedSQL(StringBuilder builder,
 int sqlFlags)

Description copied from class: Expression

Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.

Specified by:

getUnenclosedSQL in class Expression

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder