org.h2.expression

类 OperationN

java.lang.Object

org.h2.expression.Expression

org.h2.expression.OperationN

所有已实现的接口:

ExpressionWithVariableParameters, HasSQL, Typed

直接已知子类:

ConcatenationOperation, FunctionN, JsonConstructorFunction, SearchedCase

public abstract class OperationN
extends Expression
implements ExpressionWithVariableParameters

Operation with many arguments.

字段概要

字段

限定符和类型	字段和说明
protected Expression[]	args The array of arguments.
protected int	argsCount The number of arguments.
protected TypeInfo	type The type of the result.

从类继承的字段 org.h2.expression.Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

从接口继承的字段 org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

构造器概要

构造器

限定符	构造器和说明
protected	OperationN(Expression[] args)

方法概要

限定符和类型	方法和说明
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.

从类继承的方法 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

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.h2.util.HasSQL

getTraceSQL

字段详细资料

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.

构造器详细资料

OperationN

protected OperationN(Expression[] args)

方法详细资料

addParameter

public void addParameter(Expression param)

从接口复制的说明: ExpressionWithVariableParameters

Adds the parameter expression.

指定者:

addParameter 在接口中 ExpressionWithVariableParameters

参数:

param - the expression

doneWithParameters

public void doneWithParameters()
                        throws DbException

从接口复制的说明: 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.

指定者:

doneWithParameters 在接口中 ExpressionWithVariableParameters

抛出:

DbException - if the parameter count is incorrect.

getType

public TypeInfo getType()

从类复制的说明: Expression

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

指定者:

getType 在接口中 Typed

指定者:

getType 在类中 Expression

返回:

the data type

mapColumns

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

从类复制的说明: Expression

Map the columns of the resolver to expression columns.

指定者:

mapColumns 在类中 Expression

参数:

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.

参数:

session - the session

allConst - whether operation is deterministic

返回:

whether operation is deterministic and all arguments are constants

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean value)

从类复制的说明: Expression

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

指定者:

setEvaluatable 在类中 Expression

参数:

tableFilter - the table filter

value - true if the table filter can return value

updateAggregate

public void updateAggregate(SessionLocal session,
                            int stage)

从类复制的说明: 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.

指定者:

updateAggregate 在类中 Expression

参数:

session - the session

stage - select stage

isEverything

public boolean isEverything(ExpressionVisitor visitor)

从类复制的说明: Expression

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

指定者:

isEverything 在类中 Expression

参数:

visitor - the visitor

返回:

if the criteria can be fulfilled

getCost

public int getCost()

从类复制的说明: Expression

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

指定者:

getCost 在类中 Expression

返回:

the estimated cost

getSubexpressionCount

public int getSubexpressionCount()

从类复制的说明: Expression

Returns count of subexpressions.

覆盖:

getSubexpressionCount 在类中 Expression

返回:

count of subexpressions

getSubexpression

public Expression getSubexpression(int index)

从类复制的说明: Expression

Returns subexpression with specified index.

覆盖:

getSubexpression 在类中 Expression

参数:

index - 0-based index

返回:

subexpression with specified index, may be null