org.h2.expression

类 Wildcard

java.lang.Object

org.h2.expression.Expression

org.h2.expression.Wildcard

所有已实现的接口:

HasSQL, Typed

public final class Wildcard
extends Expression

A wildcard expression as in SELECT * FROM TEST. This object is only used temporarily during the parsing phase, and later replaced by column expressions.

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

构造器概要

构造器

构造器和说明
Wildcard(String schema, String table)

方法概要

限定符和类型	方法和说明
int	getCost() Estimate the cost to process the expression.
ArrayList<ExpressionColumn>	getExceptColumns()
String	getSchemaName() Get the schema name, or null
String	getTableAlias() Get the table alias name or null if this expression does not represent a column.
TypeInfo	getType() Returns the data type.
StringBuilder	getUnenclosedSQL(StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.
Value	getValue(SessionLocal session) Return the resulting value for the current row.
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.
HashMap<Column,ExpressionColumn>	mapExceptColumns() Returns map of excluded table columns to expression columns and validates that all columns are resolved and not duplicated.
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	setExceptColumns(ArrayList<ExpressionColumn> exceptColumns)
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, getSQL, getSQL, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, 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

构造器详细资料

Wildcard

public Wildcard(String schema,
                String table)

方法详细资料

getExceptColumns

public ArrayList<ExpressionColumn> getExceptColumns()

setExceptColumns

public void setExceptColumns(ArrayList<ExpressionColumn> exceptColumns)

mapExceptColumns

public HashMap<Column,ExpressionColumn> mapExceptColumns()

Returns map of excluded table columns to expression columns and validates that all columns are resolved and not duplicated.

返回:

map of excluded table columns to expression columns

getValue

public Value getValue(SessionLocal session)

从类复制的说明: Expression

Return the resulting value for the current row.

指定者:

getValue 在类中 Expression

参数:

session - the session

返回:

the result

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

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

getTableAlias

public String getTableAlias()

从类复制的说明: Expression

Get the table alias name or null if this expression does not represent a column.

覆盖:

getTableAlias 在类中 Expression

返回:

the table alias name

getSchemaName

public String getSchemaName()

从类复制的说明: Expression

Get the schema name, or null

覆盖:

getSchemaName 在类中 Expression

返回:

the schema name

getUnenclosedSQL

public StringBuilder getUnenclosedSQL(StringBuilder builder,
                                      int sqlFlags)

从类复制的说明: 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.

指定者:

getUnenclosedSQL 在类中 Expression

参数:

builder - string builder

sqlFlags - formatting flags

返回:

the specified string builder

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