org.h2.expression

Class OperationN

java.lang.Object

org.h2.expression.Expression

org.h2.expression.OperationN

All Implemented Interfaces:

ExpressionWithVariableParameters, HasSQL, Typed

Direct Known Subclasses:

ConcatenationOperation, FunctionN, JsonConstructorFunction, SearchedCase

public abstract class OperationN
extends Expression
implements ExpressionWithVariableParameters

Operation with many arguments.

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression[]	args The array of arguments.
protected int	argsCount The number of arguments.
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 and Description
protected	OperationN(Expression[] args)

Method Summary

Modifier and Type	Method and Description
void	addParameter(Expression param) Adds the parameter expression.
void	doneWithParameters() This method must be called after all the parameters have been set.
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.
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.
protected boolean	optimizeArguments(SessionLocal session, boolean allConst) Optimizes arguments.
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, getUnenclosedSQL, 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

Field Detail

args

protected Expression[] args

The array of arguments.

argsCount

protected int argsCount

The number of arguments.

type

protected TypeInfo type

The type of the result.

Constructor Detail

OperationN

protected OperationN(Expression[] args)

Method Detail

addParameter

public void addParameter(Expression param)

Description copied from interface: ExpressionWithVariableParameters

Adds the parameter expression.

Specified by:

addParameter in interface ExpressionWithVariableParameters

Parameters:

param - the expression

doneWithParameters

public void doneWithParameters()
                        throws DbException

Description copied from interface: ExpressionWithVariableParameters

This method must be called after all the parameters have been set. It checks if the parameter count is correct when required by the implementation.

Specified by:

doneWithParameters in interface ExpressionWithVariableParameters

Throws:

DbException - if the parameter count is incorrect.

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

optimizeArguments

protected boolean optimizeArguments(SessionLocal session,
                                    boolean allConst)

Optimizes arguments.

Parameters:

session - the session

allConst - whether operation is deterministic

Returns:

whether operation is deterministic and all arguments are constants

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