org.h2.expression.condition

类 SimplePredicate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.condition.SimplePredicate

所有已实现的接口:

HasSQL, Typed

直接已知子类:

BooleanTest, NullPredicate, TypePredicate

public abstract class SimplePredicate
extends Expression

Base class for simple predicates.

字段概要

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

方法概要

限定符和类型	方法和说明
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.
boolean	isWhenConditionOperand() Returns whether this expression is a right side of condition in a when operand.
void	mapColumns(ColumnResolver resolver, int level, int state) Map the columns of the resolver to expression columns.
boolean	needParentheses() Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.
Expression	optimize(SessionLocal session) Try to optimize the expression.
void	setEvaluatable(TableFilter tableFilter, boolean b) 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, 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

方法详细资料

optimize

public Expression optimize(SessionLocal session)

从类复制的说明: Expression

Try to optimize the expression.

指定者:

optimize 在类中 Expression

参数:

session - the session

返回:

the optimized expression

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean b)

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

b - true if the table filter can return value

needParentheses

public final boolean needParentheses()

从类复制的说明: Expression

Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.

覆盖:

needParentheses 在类中 Expression

返回:

true if it is

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

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

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

isWhenConditionOperand

public final boolean isWhenConditionOperand()

从类复制的说明: Expression

Returns whether this expression is a right side of condition in a when operand.

覆盖:

isWhenConditionOperand 在类中 Expression

返回:

true if it is, false otherwise

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