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Interface COM.cloudscape.vti.VTICosting

public interface VTICosting
Copyright © 1998-1999, Cloudscape, 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:
VTIEnvironment

Variable Index

 o CLASS_NAME
 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.

Variables

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

Methods

 o getEstimatedRowCount
 public abstract double getEstimatedRowCount(VTIEnvironment vtiEnvironment) throws 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: SQLException
thrown if the costing fails.
 o getEstimatedCostPerInstantiation
 public abstract double getEstimatedCostPerInstantiation(VTIEnvironment vtiEnvironment) throws 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: SQLException
thrown if the costing fails.
 o supportsMultipleInstantiations
 public abstract boolean supportsMultipleInstantiations(VTIEnvironment vtiEnvironment) throws 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: SQLException
thrown if the costing fails.

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