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org.apache.derby.impl.sql.execute
Class GenericScanQualifier  

java.lang.Object
  org.apache.derby.impl.sql.execute.GenericScanQualifier

All Implemented Interfaces:

org.apache.derby.iapi.store.access.Qualifier, org.apache.derby.iapi.sql.execute.ScanQualifier

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public class GenericScanQualifier

extends java.lang.Object

implements org.apache.derby.iapi.sql.execute.ScanQualifier

This is the implementation for ScanQualifier. It is used for system and user scans.

Version:

0.1

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Field Summary
private  int	columnId
private  boolean	negateCR
private  int	operator
private  org.apache.derby.iapi.types.DataValueDescriptor	orderable
private  boolean	orderedNulls
private  boolean	properInit
private  boolean	unknownRV

 

Fields inherited from interface org.apache.derby.iapi.store.access.Qualifier

CONSTANT, QUERY_INVARIANT, SCAN_INVARIANT, VARIANT

 

Constructor Summary

GenericScanQualifier()

 

Method Summary
void	clearOrderableCache()           Clear the DataValueDescriptor cache, if one exists.
int	getColumnId()           Get the (zero based) id of the column to be qualified.
int	getOperator()           Get the operator to use in the comparison.
org.apache.derby.iapi.types.DataValueDescriptor	getOrderable()           Get the value that the column is to be compared to.
boolean	getOrderedNulls()           Get the getOrderedNulls argument to use in the comparison.
boolean	getUnknownRV()           Get the getOrderedNulls argument to use in the comparison.
boolean	negateCompareResult()           Should the result from the compare operation be negated? If true then only rows which fail the compare operation will qualify.
void	reinitialize()           This method reinitializes all the state of the Qualifier.
void	setQualifier(int columnId, org.apache.derby.iapi.types.DataValueDescriptor orderable, int operator, boolean negateCR, boolean orderedNulls, boolean unknownRV)           Set the info in a ScanQualifier

 

Methods inherited from class java.lang.Object

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

 

Field Detail

columnId

private int columnId

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orderable

private org.apache.derby.iapi.types.DataValueDescriptor orderable

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operator

private int operator

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negateCR

private boolean negateCR

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orderedNulls

private boolean orderedNulls

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unknownRV

private boolean unknownRV

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properInit

private boolean properInit

Constructor Detail

GenericScanQualifier

public GenericScanQualifier()

Method Detail

getColumnId

public int getColumnId()

Description copied from interface: org.apache.derby.iapi.store.access.Qualifier

Get the (zero based) id of the column to be qualified.

This id is the column number of the column in the table, no matter whether a partial column set is being retrieved by the actual fetch. Note that the column being specified in the qualifier must appear in the column list being fetched.

Specified by:

getColumnId in interface org.apache.derby.iapi.store.access.Qualifier

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getOrderable

public org.apache.derby.iapi.types.DataValueDescriptor getOrderable()

Description copied from interface: org.apache.derby.iapi.store.access.Qualifier

Get the value that the column is to be compared to.

Specified by:

getOrderable in interface org.apache.derby.iapi.store.access.Qualifier

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getOperator

public int getOperator()

Get the operator to use in the comparison.

Specified by:

getOperator in interface org.apache.derby.iapi.store.access.Qualifier

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negateCompareResult

public boolean negateCompareResult()

Should the result from the compare operation be negated? If true then only rows which fail the compare operation will qualify.

Specified by:

negateCompareResult in interface org.apache.derby.iapi.store.access.Qualifier

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getOrderedNulls

public boolean getOrderedNulls()

Get the getOrderedNulls argument to use in the comparison.

Specified by:

getOrderedNulls in interface org.apache.derby.iapi.store.access.Qualifier

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getUnknownRV

public boolean getUnknownRV()

Get the getOrderedNulls argument to use in the comparison.

Specified by:

getUnknownRV in interface org.apache.derby.iapi.store.access.Qualifier

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clearOrderableCache

public void clearOrderableCache()

Clear the DataValueDescriptor cache, if one exists. (The DataValueDescriptor can be 1 of 3 types: o VARIANT - cannot be cached as its value can vary within a scan o SCAN_INVARIANT - can be cached within a scan as its value will not change within a scan o QUERY_INVARIANT- can be cached across the life of the query as its value will never change o CONSTANT - immutable

Specified by:

clearOrderableCache in interface org.apache.derby.iapi.store.access.Qualifier

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reinitialize

public void reinitialize()

This method reinitializes all the state of the Qualifier. It is used to distinguish between resetting something that is query invariant and something that is constant over every execution of a query. Basically, clearOrderableCache() will only clear out its cache if it is a VARIANT or SCAN_INVARIANT value. However, each time a query is executed, the QUERY_INVARIANT qualifiers need to be reset.

Specified by:

reinitialize in interface org.apache.derby.iapi.store.access.Qualifier

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setQualifier

public void setQualifier(int columnId,
                         org.apache.derby.iapi.types.DataValueDescriptor orderable,
                         int operator,
                         boolean negateCR,
                         boolean orderedNulls,
                         boolean unknownRV)

Description copied from interface: org.apache.derby.iapi.sql.execute.ScanQualifier

Set the info in a ScanQualifier

Specified by:

setQualifier in interface org.apache.derby.iapi.sql.execute.ScanQualifier

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> sql >> [ execute overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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