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OptimizablePredicate provides services for optimizing predicates in a query.
Method Summary | |
boolean |
compareWithKnownConstant(Optimizable optTable,
boolean considerParameters)
Is this predicate a comparison with a known constant value? |
boolean |
equalsComparisonWithConstantExpression(Optimizable optTable)
Is this predicate an equality comparison with a constant expression? |
DataValueDescriptor |
getCompareValue(Optimizable optTable)
Get an Object representing the known constant value that the given Optimizable is being compared to. |
int |
getIndexPosition()
Get the position of the index column that this predicate restricts. |
JBitSet |
getReferencedMap()
Get the map of referenced tables for this OptimizablePredicate. |
int |
hasEqualOnColumnList(int[] baseColumnPositions,
Optimizable optTable)
Returns if the predicate involves an equal operator on one of the columns specified in the baseColumnPositions. |
boolean |
hasMethodCall()
Return whether or not an OptimizablePredicate contains a method call. |
boolean |
hasSubquery()
Return whether or not an OptimizablePredicate contains a subquery. |
boolean |
isQualifier()
Is this predicate a qualifier? |
boolean |
isStartKey()
Is this predicate a start key? |
boolean |
isStopKey()
Is this predicate a stop key? |
void |
markQualifier()
Tell the predicate that it is to be used as a qualifier in an index scan. |
void |
markStartKey()
Tell the predicate that it is to be used as a column in the start key value for an index scan. |
void |
markStopKey()
Tell the predicate that it is to be used as a column in the stop key value for an index scan. |
double |
selectivity(Optimizable optTable)
Get a (crude) estimate of the selectivity of this predicate. |
Method Detail |
public JBitSet getReferencedMap()
public boolean hasSubquery()
public boolean hasMethodCall()
public void markStartKey()
public boolean isStartKey()
public void markStopKey()
public boolean isStopKey()
public void markQualifier()
public boolean isQualifier()
public boolean compareWithKnownConstant(Optimizable optTable, boolean considerParameters)
optTable
- The Optimizable that we want to know whether we
are comparing to a known constant.considerParameters
- Whether or not to consider parameters with defaults
as known constants.public DataValueDescriptor getCompareValue(Optimizable optTable) throws StandardException
StandardException
- Thrown on errorpublic boolean equalsComparisonWithConstantExpression(Optimizable optTable)
optTable
- The Optimizable for which we want to know whether
it is being equality-compared to a constant expression.public int hasEqualOnColumnList(int[] baseColumnPositions, Optimizable optTable) throws StandardException
baseColumnPositions
- the column numbers on which the user wants
to check if the equality condition exists.optTable
- the table for which baseColumnPositions are given.
StandardException
public double selectivity(Optimizable optTable)
optTable
- The Optimizable that this predicate restrictspublic int getIndexPosition()
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Built on Tue 2006-10-10 19:23:47+0200, from revision exported | |||||||||
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