Class UTFQualifier
- java.lang.Object
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- org.apache.derby.impl.store.access.UTFQualifier
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Field Summary
Fields Modifier and Type Field Description private int
columnId
private UTF
value
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Fields inherited from interface org.apache.derby.iapi.store.access.Qualifier
CONSTANT, QUERY_INVARIANT, SCAN_INVARIANT, VARIANT
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Constructor Summary
Constructors Constructor Description UTFQualifier(int columnId, java.lang.String value)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
clearOrderableCache()
Clear the DataValueDescriptor cache, if one exists.int
getColumnId()
Get the id of the column to be qualified.int
getOperator()
Get the operator to use in the comparison.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()
Determine if the result from the compare operation is to be negated.void
reinitialize()
This method reinitializes all the state of the Qualifier.
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Field Detail
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value
private UTF value
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columnId
private int columnId
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Method Detail
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getColumnId
public int getColumnId()
Get the id of the column to be qualified.- Specified by:
getColumnId
in interfaceQualifier
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getOrderable
public DataValueDescriptor getOrderable()
Get the value that the column is to be compared to.- Specified by:
getOrderable
in interfaceQualifier
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getOperator
public int getOperator()
Get the operator to use in the comparison.- Specified by:
getOperator
in interfaceQualifier
- See Also:
DataValueDescriptor.compare(org.apache.derby.iapi.types.DataValueDescriptor)
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negateCompareResult
public boolean negateCompareResult()
Determine if the result from the compare operation is to be negated.If true then only rows which fail the compare operation will qualify.
- Specified by:
negateCompareResult
in interfaceQualifier
- See Also:
DataValueDescriptor.compare(org.apache.derby.iapi.types.DataValueDescriptor)
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getOrderedNulls
public boolean getOrderedNulls()
Description copied from interface:Qualifier
Get the getOrderedNulls argument to use in the comparison.- Specified by:
getOrderedNulls
in interfaceQualifier
- See Also:
Qualifier.getOrderedNulls()
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getUnknownRV
public boolean getUnknownRV()
Get the getOrderedNulls argument to use in the comparison.- Specified by:
getUnknownRV
in interfaceQualifier
- See Also:
DataValueDescriptor.compare(org.apache.derby.iapi.types.DataValueDescriptor)
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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 - can be cached across executions- Specified by:
clearOrderableCache
in interfaceQualifier
- See Also:
Qualifier.getUnknownRV()
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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 interfaceQualifier
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