org.h2.expression

Class Wildcard

java.lang.Object

org.h2.expression.Expression

org.h2.expression.Wildcard

All Implemented Interfaces:

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.

Field Summary

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

Constructor and Description
Wildcard(java.lang.String schema, java.lang.String table)

Method Summary

Modifier and Type	Method and Description
int	getCost() Estimate the cost to process the expression.
java.util.ArrayList<ExpressionColumn>	getExceptColumns()
java.lang.String	getSchemaName() Get the schema name, or null
java.lang.String	getTableAlias() Get the table alias name or null if this expression does not represent a column.
TypeInfo	getType() Returns the data type.
java.lang.StringBuilder	getUnenclosedSQL(java.lang.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.
java.util.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(java.util.ArrayList<ExpressionColumn> exceptColumns)
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, getSQL, getSQL, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, 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

Constructor Detail

Wildcard

public Wildcard(java.lang.String schema,
                java.lang.String table)

Method Detail

getExceptColumns

public java.util.ArrayList<ExpressionColumn> getExceptColumns()

setExceptColumns

public void setExceptColumns(java.util.ArrayList<ExpressionColumn> exceptColumns)

mapExceptColumns

public java.util.HashMap<Column,ExpressionColumn> mapExceptColumns()

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

Returns:

map of excluded table columns to expression columns

getValue

public Value getValue(SessionLocal session)

Description copied from class: Expression

Return the resulting value for the current row.

Specified by:

getValue in class Expression

Parameters:

session - the session

Returns:

the result

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

optimize

public Expression optimize(SessionLocal session)

Description copied from class: Expression

Try to optimize the expression.

Specified by:

optimize in class Expression

Parameters:

session - the session

Returns:

the optimized expression

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean b)

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

b - true if the table filter can return value

getTableAlias

public java.lang.String getTableAlias()

Description copied from class: Expression

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

Overrides:

getTableAlias in class Expression

Returns:

the table alias name

getSchemaName

public java.lang.String getSchemaName()

Description copied from class: Expression

Get the schema name, or null

Overrides:

getSchemaName in class Expression

Returns:

the schema name

getUnenclosedSQL

public java.lang.StringBuilder getUnenclosedSQL(java.lang.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

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