Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.sql.compile.RelationalOperator

Modifier and Type	Field and Description
public static final int	EQUALS_RELOP
public static final int	GREATER_EQUALS_RELOP
public static final int	GREATER_THAN_RELOP
public static final int	IS_NOT_NULL_RELOP
public static final int	IS_NULL_RELOP
public static final int	LESS_EQUALS_RELOP
public static final int	LESS_THAN_RELOP
public static final int	NOT_EQUALS_RELOP

Method Summary

Modifier and Type	Method and Description
public boolean	compareWithKnownConstant(Optimizable optTable, boolean considerParameters) Return whether this operator compares the given Optimizable with a constant whose value is known at compile time.
public boolean	equalsComparisonWithConstantExpression(Optimizable optTable) Return whether this operator is an equality comparison of the given optimizable with a constant expression.
public void	generateAbsoluteColumnId(MethodBuilder The method the generated code is to go into mb, Optimizable The optimizable table we're doing the scan on. optTable) Generate the absolute column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table.
public void	generateExpressionOperand(Optimizable An Optimizable for the base table the column is in optTable, int The ordinal position of the column (one-based) columnPosition, ExpressionClassBuilderInterface The ExpressionClassBuilder for the class we're building acb, MethodBuilder The method the expression will go into mb) Check whether this RelationalOperator is a comparison of the given column with an expression.
public void	generateNegate(MethodBuilder The method the generated code is to go into mb, Optimizable The Optimizable table the Qualifier will qualify optTable) Generate an expression that evaluates to true if the result of the comparison should be negated.
public void	generateOperator(MethodBuilder The method the generated code is to go into mb, Optimizable The optimizable table we're doing the scan on. optTable) Generate the comparison operator for this RelationalOperator.
public void	generateOrderedNulls(MethodBuilder The method the generated code is to go into mb) Generate an expression that evaluates to true if this RelationalOperator uses ordered null semantics, false if it doesn't.
public void	generateQualMethod(ExpressionClassBuilderInterface The ExpressionClassBuilder for the class we're building acb, MethodBuilder The method the generated code is to go into mb, Optimizable The Optimizable table the Qualifier will qualify optTable) Generate the method to evaluate a Qualifier.
public void	generateRelativeColumnId(MethodBuilder The method the generated code is to go into mb, Optimizable The optimizable table we're doing the scan on. optTable) Generate the relative column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table.
public ColumnReference	Returns: The ColumnReference on one side of this RelationalOperator that represents the given columnPosition. Returns null if no such ColumnReference exists by itself on one side of this RelationalOperator. getColumnOperand(Optimizable An Optimizable for the base table the column is in optTable, int The ordinal position of the column (one-based) columnPosition) Check whether this RelationalOperator is a comparison of the given column with an expression.
public ColumnReference	getColumnOperand(Optimizable optTable) Get the ColumnReference for the given table on one side of this RelationalOperator.
public DataValueDescriptor	getCompareValue(Optimizable optTable) Return an Object representing the known value that this relational operator is comparing to a column in the given Optimizable.
public ValueNode	Returns: The ValueNode for the expression the column is being compared to - null if the column is not being compared to anything. getExpressionOperand(int The table number of the base table the column is in tableNumber, int The ordinal position of the column (one-based) columnPosition, Optimizable We'll look for the column in all tables at and beneath ft. This is useful if ft is, say, a ProjectRestrictNode over a subquery-- then we want to look at all of the FROM tables in the subquery to try to find the right column. ft) Check whether this RelationalOperator is a comparison of the given column with an expression.
public ValueNode	getOperand(ColumnReference The ColumnReference for which we're searching. cRef, int Size of the referenced map for the predicate represented by this RelationalOperator node. This is used for storing base table numbers when searching for cRef. refSetSize, boolean Assuming we find an operand that points to the same table as cRef, then we will return the other operand if otherSide is true; else we'll return the operand that matches cRef. otherSide) Find the operand (left or right) that points to the same table as the received ColumnReference, and then return either that operand or the "other" operand, depending on the value of otherSide.
public int	Returns: int The operator for this RelationalOperator. getOperator() Return the operator (as an int) for this RelationalOperator.
public int	Returns: int The variant type for the Qualifier's Orderable. getOrderableVariantType(Optimizable The Optimizable table the Qualifier will qualify optTable) Return the variant type for the Qualifier's Orderable.
public int	Returns: Either ScanController.GT or ScanController.GE getStartOperator(Optimizable The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on. optTable) Get the start operator for a scan (at the store level) for this RelationalOperator.
public int	Returns: Either ScanController.GT or ScanController.GE getStopOperator(Optimizable The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on. optTable) Get the stop operator for a scan (at the store level) for this RelationalOperator.
public RelationalOperator	Returns: A relational operator which matches the current one but with the passed in ColumnReference as the (left) operand. getTransitiveSearchClause(ColumnReference The ColumnReference for the new (left) operand. otherCR) Return a relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.
public boolean	Returns: true if this operator can be compiled into a Qualifier for the given Optimizable table. isQualifier(Optimizable The Optimizable table in question. optTable, boolean Are we asking because we're trying to push? forPush) Return true if this operator can be compiled into a Qualifier for the given Optimizable table.
public boolean	orderedNulls() Return true if this operator uses ordered null semantics
public boolean	Returns: true if the given ColumnReference is being compared to any columns from the same table selfComparison(ColumnReference The ColumnReference that is being compared to some expression. cr) Check whether this RelationalOperator compares the given ColumnReference to any columns in the same table as the ColumnReference.
public boolean	Returns: true if this is a useful start key usefulStartKey(Optimizable The Optimizable table for which we want to know whether this is a useful start key. optTable) Tell whether this relop is a useful start key for the given table.
public boolean	Returns: true if this is a useful stop key usefulStopKey(Optimizable The Optimizable table for which we want to know whether this is a useful stop key. optTable) Tell whether this relop is a useful stop key for the given table.

EQUALS_RELOP	back to summary
public static final int EQUALS_RELOP

GREATER_EQUALS_RELOP	back to summary
public static final int GREATER_EQUALS_RELOP

GREATER_THAN_RELOP	back to summary
public static final int GREATER_THAN_RELOP

IS_NOT_NULL_RELOP	back to summary
public static final int IS_NOT_NULL_RELOP

IS_NULL_RELOP	back to summary
public static final int IS_NULL_RELOP

LESS_EQUALS_RELOP	back to summary
public static final int LESS_EQUALS_RELOP

LESS_THAN_RELOP	back to summary
public static final int LESS_THAN_RELOP

NOT_EQUALS_RELOP	back to summary
public static final int NOT_EQUALS_RELOP

Method Detail

compareWithKnownConstant	back to summary
public boolean compareWithKnownConstant(Optimizable optTable, boolean considerParameters) Return whether this operator compares the given Optimizable with a constant whose value is known at compile time.

equalsComparisonWithConstantExpression	back to summary
public boolean equalsComparisonWithConstantExpression(Optimizable optTable) Return whether this operator is an equality comparison of the given optimizable with a constant expression.

generateAbsoluteColumnId	back to summary
public void generateAbsoluteColumnId(MethodBuilder mb, Optimizable optTable) Generate the absolute column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table. (Absolute column id means column id within the row stored on disk.) Parameters mb:MethodBuilder The method the generated code is to go into optTable:Optimizable The optimizable table we're doing the scan on.

generateAbsoluteColumnId

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public void generateAbsoluteColumnId(MethodBuilder mb, Optimizable optTable)

Generate the absolute column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table. (Absolute column id means column id within the row stored on disk.)

Parameters

mb:MethodBuilder: The method the generated code is to go into
optTable:Optimizable: The optimizable table we're doing the scan on.

generateExpressionOperand	back to summary
public void generateExpressionOperand(Optimizable optTable, int columnPosition, ExpressionClassBuilderInterface acb, MethodBuilder mb) throws StandardException Check whether this RelationalOperator is a comparison of the given column with an expression. If so, generate the Expression for the ValueNode that the column is being compared to. Parameters optTable:Optimizable An Optimizable for the base table the column is in columnPosition:int The ordinal position of the column (one-based) acb:ExpressionClassBuilderInterface The ExpressionClassBuilder for the class we're building mb:MethodBuilder The method the expression will go into Exceptions StandardException: Thrown on error

generateExpressionOperand

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public void generateExpressionOperand(Optimizable optTable, int columnPosition, ExpressionClassBuilderInterface acb, MethodBuilder mb) throws StandardException

Check whether this RelationalOperator is a comparison of the given column with an expression. If so, generate the Expression for the ValueNode that the column is being compared to.

Parameters

optTable:Optimizable: An Optimizable for the base table the column is in
columnPosition:int: The ordinal position of the column (one-based)
acb:ExpressionClassBuilderInterface: The ExpressionClassBuilder for the class we're building
mb:MethodBuilder: The method the expression will go into

Exceptions

StandardException:: Thrown on error

generateNegate	back to summary
public void generateNegate(MethodBuilder mb, Optimizable optTable) Generate an expression that evaluates to true if the result of the comparison should be negated. For example, col > 1 generates a comparison operator of <= and a negation of true, while col < 1 generates a comparison operator of < and a negation of false. Parameters mb:MethodBuilder The method the generated code is to go into optTable:Optimizable The Optimizable table the Qualifier will qualify

generateNegate

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public void generateNegate(MethodBuilder mb, Optimizable optTable)

Generate an expression that evaluates to true if the result of the comparison should be negated. For example, col > 1 generates a comparison operator of <= and a negation of true, while col < 1 generates a comparison operator of < and a negation of false.

Parameters

mb:MethodBuilder: The method the generated code is to go into
optTable:Optimizable: The Optimizable table the Qualifier will qualify

generateOperator	back to summary
public void generateOperator(MethodBuilder mb, Optimizable optTable) Generate the comparison operator for this RelationalOperator. The operator can depend on which side of this operator the optimizable column is. Parameters mb:MethodBuilder The method the generated code is to go into optTable:Optimizable The optimizable table we're doing the scan on.

generateOperator

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public void generateOperator(MethodBuilder mb, Optimizable optTable)

Generate the comparison operator for this RelationalOperator. The operator can depend on which side of this operator the optimizable column is.

Parameters

mb:MethodBuilder: The method the generated code is to go into
optTable:Optimizable: The optimizable table we're doing the scan on.

generateOrderedNulls	back to summary
public void generateOrderedNulls(MethodBuilder mb) Generate an expression that evaluates to true if this RelationalOperator uses ordered null semantics, false if it doesn't. Parameters mb:MethodBuilder The method the generated code is to go into

generateOrderedNulls

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public void generateOrderedNulls(MethodBuilder mb)

Generate an expression that evaluates to true if this RelationalOperator uses ordered null semantics, false if it doesn't.

Parameters

mb:MethodBuilder: The method the generated code is to go into

generateQualMethod	back to summary
public void generateQualMethod(ExpressionClassBuilderInterface acb, MethodBuilder mb, Optimizable optTable) throws StandardException Generate the method to evaluate a Qualifier. The factory method for a Qualifier takes a GeneratedMethod that returns the Orderable that Qualifier.getOrderable() returns. Parameters acb:ExpressionClassBuilderInterface The ExpressionClassBuilder for the class we're building mb:MethodBuilder The method the generated code is to go into optTable:Optimizable The Optimizable table the Qualifier will qualify Exceptions StandardException: Thrown on error.

generateQualMethod

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public void generateQualMethod(ExpressionClassBuilderInterface acb, MethodBuilder mb, Optimizable optTable) throws StandardException

Generate the method to evaluate a Qualifier. The factory method for a Qualifier takes a GeneratedMethod that returns the Orderable that Qualifier.getOrderable() returns.

Parameters

acb:ExpressionClassBuilderInterface: The ExpressionClassBuilder for the class we're building
mb:MethodBuilder: The method the generated code is to go into
optTable:Optimizable: The Optimizable table the Qualifier will qualify

Exceptions

StandardException:: Thrown on error.

generateRelativeColumnId	back to summary
public void generateRelativeColumnId(MethodBuilder mb, Optimizable optTable) Generate the relative column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table. (Relative column id means column id within the partial row returned by the store.) Parameters mb:MethodBuilder The method the generated code is to go into optTable:Optimizable The optimizable table we're doing the scan on.

generateRelativeColumnId

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public void generateRelativeColumnId(MethodBuilder mb, Optimizable optTable)

Generate the relative column id for the ColumnReference that appears on one side of this RelationalOperator or the other, and that refers to the given table. (Relative column id means column id within the partial row returned by the store.)

Parameters

mb:MethodBuilder: The method the generated code is to go into
optTable:Optimizable: The optimizable table we're doing the scan on.

getColumnOperand	back to summary
public ColumnReference getColumnOperand(Optimizable optTable, int columnPosition) Check whether this RelationalOperator is a comparison of the given column with an expression. If so, return the ColumnReference that corresponds to the given column, and that is on one side of this RelationalOperator or the other (this method copes with the column being on either side of the operator). If the given column does not appear by itself on one side of the comparison, the method returns null. Parameters optTable:Optimizable An Optimizable for the base table the column is in columnPosition:int The ordinal position of the column (one-based) Returns:ColumnReference The ColumnReference on one side of this RelationalOperator that represents the given columnPosition. Returns null if no such ColumnReference exists by itself on one side of this RelationalOperator.

getColumnOperand

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public ColumnReference getColumnOperand(Optimizable optTable, int columnPosition)

Check whether this RelationalOperator is a comparison of the given column with an expression. If so, return the ColumnReference that corresponds to the given column, and that is on one side of this RelationalOperator or the other (this method copes with the column being on either side of the operator). If the given column does not appear by itself on one side of the comparison, the method returns null.

Parameters

optTable:Optimizable: An Optimizable for the base table the column is in
columnPosition:int: The ordinal position of the column (one-based)

Returns:ColumnReference

The ColumnReference on one side of this RelationalOperator that represents the given columnPosition. Returns null if no such ColumnReference exists by itself on one side of this RelationalOperator.

getColumnOperand	back to summary
public ColumnReference getColumnOperand(Optimizable optTable) Get the ColumnReference for the given table on one side of this RelationalOperator. This presumes it will be found only on one side. If not found, it will return null.

getCompareValue	back to summary
public DataValueDescriptor getCompareValue(Optimizable optTable) throws StandardException Return an Object representing the known value that this relational operator is comparing to a column in the given Optimizable. Exceptions StandardException: Thrown on error

getCompareValue

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public DataValueDescriptor getCompareValue(Optimizable optTable) throws StandardException

Return an Object representing the known value that this relational operator is comparing to a column in the given Optimizable.

Exceptions

StandardException:: Thrown on error

getExpressionOperand	back to summary
public ValueNode getExpressionOperand(int tableNumber, int columnPosition, Optimizable ft) Check whether this RelationalOperator is a comparison of the given column with an expression. If so, return the expression the column is being compared to. Parameters tableNumber:int The table number of the base table the column is in columnPosition:int The ordinal position of the column (one-based) ft:Optimizable We'll look for the column in all tables at and beneath ft. This is useful if ft is, say, a ProjectRestrictNode over a subquery-- then we want to look at all of the FROM tables in the subquery to try to find the right column. Returns:ValueNode The ValueNode for the expression the column is being compared to - null if the column is not being compared to anything.

getExpressionOperand

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public ValueNode getExpressionOperand(int tableNumber, int columnPosition, Optimizable ft)

Check whether this RelationalOperator is a comparison of the given column with an expression. If so, return the expression the column is being compared to.

Parameters

tableNumber:int: The table number of the base table the column is in
columnPosition:int: The ordinal position of the column (one-based)
ft:Optimizable: We'll look for the column in all tables at and beneath ft. This is useful if ft is, say, a ProjectRestrictNode over a subquery-- then we want to look at all of the FROM tables in the subquery to try to find the right column.

Returns:ValueNode

The ValueNode for the expression the column is being compared to - null if the column is not being compared to anything.

getOperand	back to summary
public ValueNode getOperand(ColumnReference cRef, int refSetSize, boolean otherSide) Find the operand (left or right) that points to the same table as the received ColumnReference, and then return either that operand or the "other" operand, depending on the value of otherSide. This presumes it will be found only on one side. If not found, it will return null. Parameters cRef:ColumnReference The ColumnReference for which we're searching. refSetSize:int Size of the referenced map for the predicate represented by this RelationalOperator node. This is used for storing base table numbers when searching for cRef. otherSide:boolean Assuming we find an operand that points to the same table as cRef, then we will return the other operand if otherSide is true; else we'll return the operand that matches cRef.

getOperand

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public ValueNode getOperand(ColumnReference cRef, int refSetSize, boolean otherSide)

Find the operand (left or right) that points to the same table as the received ColumnReference, and then return either that operand or the "other" operand, depending on the value of otherSide. This presumes it will be found only on one side. If not found, it will return null.

Parameters

cRef:ColumnReference: The ColumnReference for which we're searching.
refSetSize:int: Size of the referenced map for the predicate represented by this RelationalOperator node. This is used for storing base table numbers when searching for cRef.
otherSide:boolean: Assuming we find an operand that points to the same table as cRef, then we will return the *other* operand if otherSide is true; else we'll return the operand that matches cRef.

getOperator	back to summary
public int getOperator() Return the operator (as an int) for this RelationalOperator. Returns:int int The operator for this RelationalOperator.

getOperator

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public int getOperator()

Return the operator (as an int) for this RelationalOperator.

Returns:int: int The operator for this RelationalOperator.

getOrderableVariantType	back to summary
public int getOrderableVariantType(Optimizable optTable) throws StandardException Return the variant type for the Qualifier's Orderable. (Is the Orderable invariant within a scan or within a query?) Parameters optTable:Optimizable The Optimizable table the Qualifier will qualify Returns:int int The variant type for the Qualifier's Orderable. Exceptions StandardException: thrown on error

getOrderableVariantType

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public int getOrderableVariantType(Optimizable optTable) throws StandardException

Return the variant type for the Qualifier's Orderable. (Is the Orderable invariant within a scan or within a query?)

Parameters

optTable:Optimizable: The Optimizable table the Qualifier will qualify

Returns:int

int The variant type for the Qualifier's Orderable.

Exceptions

StandardException:: thrown on error

getStartOperator back to summary

getStartOperator	back to summary
public int getStartOperator(Optimizable optTable) Get the start operator for a scan (at the store level) for this RelationalOperator. Parameters optTable:Optimizable The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on. Returns:int Either ScanController.GT or ScanController.GE See Also `TransactionController#openScan`

public int getStartOperator(Optimizable optTable)

Get the start operator for a scan (at the store level) for this RelationalOperator.

Parameters

optTable:Optimizable: The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on.

Returns:int

Either ScanController.GT or ScanController.GE

See Also

TransactionController#openScan

getStopOperator back to summary

getStopOperator	back to summary
public int getStopOperator(Optimizable optTable) Get the stop operator for a scan (at the store level) for this RelationalOperator. Parameters optTable:Optimizable The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on. Returns:int Either ScanController.GT or ScanController.GE See Also `TransactionController#openScan`

public int getStopOperator(Optimizable optTable)

Get the stop operator for a scan (at the store level) for this RelationalOperator.

Parameters

optTable:Optimizable: The optimizable table we're doing the scan on. This parameter is so we can tell which side of the operator the table's column is on.

Returns:int

Either ScanController.GT or ScanController.GE

See Also

TransactionController#openScan

getTransitiveSearchClause	back to summary
public RelationalOperator getTransitiveSearchClause(ColumnReference otherCR) throws StandardException Return a relational operator which matches the current one but with the passed in ColumnReference as the (left) operand. Parameters otherCR:ColumnReference The ColumnReference for the new (left) operand. Returns:RelationalOperator A relational operator which matches the current one but with the passed in ColumnReference as the (left) operand. Exceptions StandardException: Thrown on error

getTransitiveSearchClause

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public RelationalOperator getTransitiveSearchClause(ColumnReference otherCR) throws StandardException

Return a relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.

Parameters

otherCR:ColumnReference: The ColumnReference for the new (left) operand.

Returns:RelationalOperator

A relational operator which matches the current one but with the passed in ColumnReference as the (left) operand.

Exceptions

StandardException:: Thrown on error

isQualifier	back to summary
public boolean isQualifier(Optimizable optTable, boolean forPush) throws StandardException Return true if this operator can be compiled into a Qualifier for the given Optimizable table. This means that there is a column from that table on one side of this relop, and an expression that does not refer to the table on the other side of the relop. Note that this method has two uses: 1) see if this operator (or more specifically, the predicate to which this operator belongs) can be used as a join predicate (esp. for a hash join), and 2) see if this operator can be pushed to the target optTable. We use the parameter "forPush" to distinguish between the two uses because in some cases (esp. situations where we have subqueries) the answer to "is this a qualifier?" can differ depending on whether or not we're pushing. In particular, for binary ops that are join predicates, if we're just trying to find an equijoin predicate then this op qualifies if it references either the target table OR any of the base tables in the table's subtree. But if we're planning to push the predicate down to the target table, this op only qualifies if it references the target table directly. This difference in behavior is required because in case 1 (searching for join predicates), the operator remains at its current level in the tree even if its operands reference nodes further down; in case 2, though, we'll end up pushing the operator down the tree to child node(s) and that requires additional logic, such as "scoping" consideration. Until that logic is in place, we don't search a subtree if the intent is to push the predicate to which this operator belongs further down that subtree. See BinaryRelationalOperatorNode for an example of where this comes into play. Parameters optTable:Optimizable The Optimizable table in question. forPush:boolean Are we asking because we're trying to push? Returns:boolean true if this operator can be compiled into a Qualifier for the given Optimizable table. Exceptions StandardException: Thrown on error

isQualifier

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public boolean isQualifier(Optimizable optTable, boolean forPush) throws StandardException

Return true if this operator can be compiled into a Qualifier for the given Optimizable table. This means that there is a column from that table on one side of this relop, and an expression that does not refer to the table on the other side of the relop. Note that this method has two uses: 1) see if this operator (or more specifically, the predicate to which this operator belongs) can be used as a join predicate (esp. for a hash join), and 2) see if this operator can be pushed to the target optTable. We use the parameter "forPush" to distinguish between the two uses because in some cases (esp. situations where we have subqueries) the answer to "is this a qualifier?" can differ depending on whether or not we're pushing. In particular, for binary ops that are join predicates, if we're just trying to find an equijoin predicate then this op qualifies if it references either the target table OR any of the base tables in the table's subtree. But if we're planning to push the predicate down to the target table, this op only qualifies if it references the target table directly. This difference in behavior is required because in case 1 (searching for join predicates), the operator remains at its current level in the tree even if its operands reference nodes further down; in case 2, though, we'll end up pushing the operator down the tree to child node(s) and that requires additional logic, such as "scoping" consideration. Until that logic is in place, we don't search a subtree if the intent is to push the predicate to which this operator belongs further down that subtree. See BinaryRelationalOperatorNode for an example of where this comes into play.

Parameters

optTable:Optimizable: The Optimizable table in question.
forPush:boolean: Are we asking because we're trying to push?

Returns:boolean

true if this operator can be compiled into a Qualifier for the given Optimizable table.

Exceptions

StandardException:: Thrown on error

orderedNulls	back to summary
public boolean orderedNulls() Return true if this operator uses ordered null semantics

selfComparison	back to summary
public boolean selfComparison(ColumnReference cr) throws StandardException Check whether this RelationalOperator compares the given ColumnReference to any columns in the same table as the ColumnReference. Parameters cr:ColumnReference The ColumnReference that is being compared to some expression. Returns:boolean true if the given ColumnReference is being compared to any columns from the same table Exceptions StandardException: Thrown on error

selfComparison

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public boolean selfComparison(ColumnReference cr) throws StandardException

Check whether this RelationalOperator compares the given ColumnReference to any columns in the same table as the ColumnReference.

Parameters

cr:ColumnReference: The ColumnReference that is being compared to some expression.

Returns:boolean

true if the given ColumnReference is being compared to any columns from the same table

Exceptions

StandardException:: Thrown on error

usefulStartKey	back to summary
public boolean usefulStartKey(Optimizable optTable) Tell whether this relop is a useful start key for the given table. It has already been determined that the relop has a column from the given table on one side or the other. Parameters optTable:Optimizable The Optimizable table for which we want to know whether this is a useful start key. Returns:boolean true if this is a useful start key

usefulStartKey

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public boolean usefulStartKey(Optimizable optTable)

Tell whether this relop is a useful start key for the given table. It has already been determined that the relop has a column from the given table on one side or the other.

Parameters

optTable:Optimizable: The Optimizable table for which we want to know whether this is a useful start key.

Returns:boolean

true if this is a useful start key

usefulStopKey	back to summary
public boolean usefulStopKey(Optimizable optTable) Tell whether this relop is a useful stop key for the given table. It has already been determined that the relop has a column from the given table on one side or the other. Parameters optTable:Optimizable The Optimizable table for which we want to know whether this is a useful stop key. Returns:boolean true if this is a useful stop key

usefulStopKey

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public boolean usefulStopKey(Optimizable optTable)

Tell whether this relop is a useful stop key for the given table. It has already been determined that the relop has a column from the given table on one side or the other.

Parameters

optTable:Optimizable: The Optimizable table for which we want to know whether this is a useful stop key.

Returns:boolean

true if this is a useful stop key

pack-priv Interface RelationalOperator

Field Summary

Method Summary

Field Detail

Method Detail