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Interface COM.cloudscape.vti.VTICosting


public interface VTICosting
Copyright © 1998-2000, Informix Software, Inc. All rights reserved.

VTICosting is the interface that the query optimizer uses to cost VTIs. The methods on the interface provide the optimizer with the following information:

This class can only be used within an SQL-J statement. Using the methods in application-side Java code results in Exceptions being thrown.

Cloudscape reserves the right to change, rename, or remove this interface at any time.

See Also:
COM.cloudscape.database.VTIEnvironment

Variable Index

 o defaultEstimatedCost
 
 o defaultEstimatedRowCount
Useful constants:

Method Index

 o getEstimatedCostPerInstantiation(VTIEnvironment)
Get the estimated cost for a single instantiation of a VTI.
 o getEstimatedRowCount(VTIEnvironment)
Get the estimated row count for a single scan of a VTI.
 o supportsMultipleInstantiations(VTIEnvironment)
Find out if the VTI can be instantiated multiple times.

Field Detail

 o defaultEstimatedRowCount
public static final double defaultEstimatedRowCount
          Useful constants:
 o defaultEstimatedCost
public static final double defaultEstimatedCost

Method Detail

 o getEstimatedRowCount
public double getEstimatedRowCount(VTIEnvironment vtiEnvironment) throws java.sql.SQLException
          Get the estimated row count for a single scan of a VTI.
Parameters:
vtiEnvironment - The VTIEnvironment.
Returns:
The estimated row count for a single scan of a VTI.
Throws:
java.sql.SQLException - thrown if the costing fails.
 o getEstimatedCostPerInstantiation
public double getEstimatedCostPerInstantiation(VTIEnvironment vtiEnvironment) throws java.sql.SQLException
          Get the estimated cost for a single instantiation of a VTI.
Parameters:
vtiEnvironment - The VTIEnvironment.
Returns:
The estimated cost for a single instantiation of a VTI.
Throws:
java.sql.SQLException - thrown if the costing fails.
 o supportsMultipleInstantiations
public boolean supportsMultipleInstantiations(VTIEnvironment vtiEnvironment) throws java.sql.SQLException
          Find out if the VTI can be instantiated multiple times.
Parameters:
vtiEnvironment - The VTIEnvironment.
Returns:
The whether or not the VTI can be instantiated multiple times.
Throws:
java.sql.SQLException - thrown if the costing fails.

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