Wildcard

java.lang.Object
- org.h2.expression.Expression
- - org.h2.expression.Wildcard

```
public 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.

Constructor Summary

Constructors
Constructor and Description

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

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

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`getCost()` Estimate the cost to process the expression.
`int`	`getDisplaySize()` Get the display size of this expression.
`long`	`getPrecision()` Get the precision of this expression.
`int`	`getScale()` Get the scale of this expression.
`java.lang.String`	`getSchemaName()` Get the schema name, or null
`java.lang.String`	`getSQL()` Get the SQL statement of this expression.
`java.lang.String`	`getTableAlias()` Get the table alias name or null if this expression does not represent a column.
`int`	`getType()` Return the data type.
`Value`	`getValue(Session 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.
`boolean`	`isWildcard()` Only returns true if the expression is a wildcard.
`void`	`mapColumns(ColumnResolver resolver, int level)` Map the columns of the resolver to expression columns.
`Expression`	`optimize(Session 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(Session session)` Update an aggregate value.

Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNotIfPossible, getNullable, getTableName, isAutoIncrement, isConstant, isValueSet, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Wildcard
```
public Wildcard(java.lang.String schema,
                java.lang.String table)
```
- Method Detail
  - isWildcard
```
public boolean isWildcard()
```
    Description copied from class: Expression
    
    Only returns true if the expression is a wildcard.
    
    Overrides:
    
    isWildcard in class Expression
    
    Returns:
    
    if this expression is a wildcard
  - getValue
```
public Value getValue(Session 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 int getType()
```
    Description copied from class: Expression
    
    Return the data type. The data type may not be known before the optimization phase.
    
    Specified by:
    
    getType in class Expression
    
    Returns:
    
    the type
  - mapColumns
```
public void mapColumns(ColumnResolver resolver,
                       int level)
```
    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
  - optimize
```
public Expression optimize(Session 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
  - getScale
```
public int getScale()
```
    Description copied from class: Expression
    
    Get the scale of this expression.
    
    Specified by:
    
    getScale in class Expression
    
    Returns:
    
    the scale
  - getPrecision
```
public long getPrecision()
```
    Description copied from class: Expression
    
    Get the precision of this expression.
    
    Specified by:
    
    getPrecision in class Expression
    
    Returns:
    
    the precision
  - getDisplaySize
```
public int getDisplaySize()
```
    Description copied from class: Expression
    
    Get the display size of this expression.
    
    Specified by:
    
    getDisplaySize in class Expression
    
    Returns:
    
    the display size
  - 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
  - getSQL
```
public java.lang.String getSQL()
```
    Description copied from class: Expression
    
    Get the SQL statement of this expression. This may not always be the original SQL statement, specially after optimization.
    
    Specified by:
    
    getSQL in class Expression
    
    Returns:
    
    the SQL statement
  - updateAggregate
```
public void updateAggregate(Session session)
```
    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
  - 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

Class Wildcard

Constructor Summary

Method Summary

Methods inherited from class org.h2.expression.Expression

Methods inherited from class java.lang.Object

Constructor Detail

Wildcard

Method Detail

isWildcard

getValue

getType

mapColumns

optimize

setEvaluatable

getScale

getPrecision

getDisplaySize

getTableAlias

getSchemaName

getSQL

updateAggregate

isEverything

getCost