com.caucho.db.sql
Class ExistsExpr

java.lang.Object
  com.caucho.db.sql.Expr
      com.caucho.db.sql.SubSelectExpr
          com.caucho.db.sql.ExistsExpr

public class ExistsExpr
extends SubSelectExpr

Field Summary

protected static L10N

L

Fields inherited from class com.caucho.db.sql.Expr

FALSE, TRUE, UNKNOWN

Method Summary

protected Expr	bind(Query query) Binds the expression to the query.
int	evalBoolean(QueryContext context) Evaluates the expression as a string.
java.lang.Class	getType() Returns the expected result type of the expression.
boolean	isNull(QueryContext context) Evaluates the expression to check for null
long	subCost(java.util.ArrayList<com.caucho.db.sql.FromItem> fromList) Returns the cost based on the given FromList.
java.lang.String	toString()

Methods inherited from class com.caucho.db.sql.SubSelectExpr

evalString, getSubSelect

Methods inherited from class com.caucho.db.sql.Expr

cost, createOrder, evalDate, evalDouble, evalGroup, evalLong, evalStream, evalToBuffer, evalToBuffer, evalToResult, getIndexExpr, getName, getSQLType, getTable, initGroup, isBinaryStream, isBoolean, isDouble, isLong, isSelect, splitAnd

Methods inherited from class java.lang.Object

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

Field Detail

L

protected static final L10N L

Method Detail

bind

protected Expr bind(Query query)
             throws java.sql.SQLException

Binds the expression to the query.

Overrides:

bind in class SubSelectExpr

Throws:

java.sql.SQLException

getType

public java.lang.Class getType()

Returns the expected result type of the expression.

Overrides:

getType in class SubSelectExpr

subCost

public long subCost(java.util.ArrayList<com.caucho.db.sql.FromItem> fromList)

Returns the cost based on the given FromList.

Overrides:

subCost in class SubSelectExpr

isNull

public boolean isNull(QueryContext context)
               throws java.sql.SQLException

Evaluates the expression to check for null

Overrides:

isNull in class Expr

Parameters:

rows - the current database tuple

Returns:

the null value

Throws:

java.sql.SQLException

evalBoolean

public int evalBoolean(QueryContext context)
                throws java.sql.SQLException

Evaluates the expression as a string.

Overrides:

evalBoolean in class Expr

Parameters:

rows - the current database tuple

Returns:

the string value

Throws:

java.sql.SQLException

toString

public java.lang.String toString()

Overrides:

toString in class SubSelectExpr