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

Modifier and Type	Field and Description
private int	addedColumnOffset If this sort key is added to the result column list then it is at result column position 1 + resultColumnList.size() - resultColumnList.getOrderBySelect() + addedColumnOffset If the sort key is already in the result column list then addedColumnOffset < 0.
private boolean	ascending
private ValueNode	expression
private OrderByList	list
private boolean	nullsOrderedLow
private ResultColumn	resultCol

Access	Constructor and Description
pack-priv	OrderByColumn(ValueNode Expression of this column expression, ContextManager The context manager cm) Constructor.

Method Summary

Modifier and Type	Method and Description
pack-priv void	acceptChildren(Visitor the visitor v) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren. Accept the visitor for all visitable children of this node.
pack-priv void	bindOrderByColumn(ResultSetNode The result set being selected from target, OrderByList OrderByList which contains this column oblist) Bind this column.
pack-priv void	clearAddedColumnOffset() Reset addedColumnOffset to indicate that column is no longer added An added column is one which was artificially added to the result column list due to its presence in the ORDER BY clause, as opposed to having been explicitly selected by the user.
pack-priv void	collapseAddedColumnGap(int offset of the column which has just been removed from list gap) Adjust addedColumnOffset to reflect that a column has been removed This routine is called when a previously-added result column has been removed due to being detected as a duplicate.
private boolean	Returns: whether a match found or not columnMatchFound(ResultSetNode result set target, ColumnReference the CR to be checked crOfExpression) This method checks a ColumnReference of this OrderByColumn against the ColumnReferences of the select clause of the query.
pack-priv boolean	constantColumn(PredicateList whereClause) Is this OrderByColumn constant, according to the given predicate list?
private boolean	Returns: boolean: whether any expression match found expressionMatch(ResultSetNode Result set target) Checks whether the whole expression (OrderByColumn) itself found in the select clause.
pack-priv ValueNode	getExpression()
pack-priv ValueNode	getNonRedundantExpression() Get the underlying expression, skipping over ResultColumns that are marked redundant.
pack-priv ResultColumn	Returns: The underlying ResultColumn. getResultColumn() Get the underlying ResultColumn.
pack-priv boolean	Returns: true if ascending, false if descending isAscending() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isAscending. Get the column order.
pack-priv boolean	Returns: true if NULLs ordered low, false if NULLs ordered high isNullsOrderedLow() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isNullsOrderedLow. Get the column NULL ordering.
private static boolean	isReferedColByNum(ValueNode expression)
pack-priv void	printSubNodes(int The depth of this node in the tree depth) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes. Prints the sub-nodes of this object.
pack-priv void	pullUpOrderByColumn(ResultSetNode The result set being selected from target) Pull up this orderby column if it doesn't appear in the resultset
pack-priv void	remapColumnReferencesToExpressions() Remap all the column references under this OrderByColumn to their expressions.
pack-priv void	resetToSourceRC() Order by columns now point to the PRN above the node of interest.
private void	resolveAddedColumn(ResultSetNode target) Assuming this OrderByColumn was "pulled" into the received target's ResultColumnList (because it wasn't there to begin with), use this.addedColumnOffset to figure out which of the target's result columns is the one corresponding to "this".
private ResultColumn	resolveColumnReference(ResultSetNode target, ColumnReference cr)
pack-priv void	setDescending() Mark the column as descending order
pack-priv void	setNullsOrderedLow() Mark the column as ordered NULL values lower than non-NULL values.
public String	Returns: This object as a String toString() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.toString. Convert this object to a String.

Inherited from org.apache.derby.impl.sql.compile.OrderedColumn:: getColumnPosition setColumnPosition

addedColumnOffset	back to summary
private int addedColumnOffset If this sort key is added to the result column list then it is at result column position 1 + resultColumnList.size() - resultColumnList.getOrderBySelect() + addedColumnOffset If the sort key is already in the result column list then addedColumnOffset < 0.

ascending	back to summary
private boolean ascending

expression	back to summary
private ValueNode expression

list	back to summary
private OrderByList list

nullsOrderedLow	back to summary
private boolean nullsOrderedLow

resultCol	back to summary
private ResultColumn resultCol

OrderByColumn	back to summary
pack-priv OrderByColumn(ValueNode expression, ContextManager cm) Constructor. Parameters expression:ValueNode Expression of this column cm:ContextManager The context manager

Method Detail

acceptChildren	back to summary
pack-priv void acceptChildren(Visitor v) throws StandardException Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren. Accept the visitor for all visitable children of this node. Parameters v:Visitor the visitor Annotations @Override Exceptions StandardException: on error

acceptChildren

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pack-priv void acceptChildren(Visitor v) throws StandardException

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren.

Accept the visitor for all visitable children of this node.

Parameters

v:Visitor: the visitor

Annotations

@Override

Exceptions

StandardException:: on error

bindOrderByColumn	back to summary
pack-priv void bindOrderByColumn(ResultSetNode target, OrderByList oblist) throws StandardException Bind this column. During binding, we may discover that this order by column was pulled up into the result column list, but is now a duplicate, because the actual result column was expanded into the result column list when "*" expressions were replaced with the list of the table's columns. In such a situation, we will end up calling back to the OrderByList to adjust the addedColumnOffset values of the columns; the "oblist" parameter exists to allow that callback to be performed. Parameters target:ResultSetNode The result set being selected from oblist:OrderByList OrderByList which contains this column Exceptions StandardException: Thrown on error Thrown when column not found

bindOrderByColumn

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pack-priv void bindOrderByColumn(ResultSetNode target, OrderByList oblist) throws StandardException

Bind this column. During binding, we may discover that this order by column was pulled up into the result column list, but is now a duplicate, because the actual result column was expanded into the result column list when "*" expressions were replaced with the list of the table's columns. In such a situation, we will end up calling back to the OrderByList to adjust the addedColumnOffset values of the columns; the "oblist" parameter exists to allow that callback to be performed.

Parameters

target:ResultSetNode: The result set being selected from
oblist:OrderByList: OrderByList which contains this column

Exceptions

StandardException:

Thrown on error
Thrown when column not found

clearAddedColumnOffset	back to summary
pack-priv void clearAddedColumnOffset() Reset addedColumnOffset to indicate that column is no longer added An added column is one which was artificially added to the result column list due to its presence in the ORDER BY clause, as opposed to having been explicitly selected by the user. Since * is not expanded until after the ORDER BY columns have been pulled up, we may add a column, then later decide it is a duplicate of an explicitly selected column. In that case, this method is called, and it does the following: - resets addedColumnOffset to -1 to indicate this is not an added col - calls back to the OrderByList to adjust any other added cols

clearAddedColumnOffset

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pack-priv void clearAddedColumnOffset()

Reset addedColumnOffset to indicate that column is no longer added An added column is one which was artificially added to the result column list due to its presence in the ORDER BY clause, as opposed to having been explicitly selected by the user. Since * is not expanded until after the ORDER BY columns have been pulled up, we may add a column, then later decide it is a duplicate of an explicitly selected column. In that case, this method is called, and it does the following: - resets addedColumnOffset to -1 to indicate this is not an added col - calls back to the OrderByList to adjust any other added cols

collapseAddedColumnGap	back to summary
pack-priv void collapseAddedColumnGap(int gap) Adjust addedColumnOffset to reflect that a column has been removed This routine is called when a previously-added result column has been removed due to being detected as a duplicate. If that added column had a lower offset than our column, we decrement our offset to reflect that we have just been moved down one slot in the result column list. Parameters gap:int offset of the column which has just been removed from list

collapseAddedColumnGap

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pack-priv void collapseAddedColumnGap(int gap)

Adjust addedColumnOffset to reflect that a column has been removed This routine is called when a previously-added result column has been removed due to being detected as a duplicate. If that added column had a lower offset than our column, we decrement our offset to reflect that we have just been moved down one slot in the result column list.

Parameters

gap:int: offset of the column which has just been removed from list

columnMatchFound	back to summary
private boolean columnMatchFound(ResultSetNode target, ColumnReference crOfExpression) throws StandardException This method checks a ColumnReference of this OrderByColumn against the ColumnReferences of the select clause of the query. Parameters target:ResultSetNode result set crOfExpression:ColumnReference the CR to be checked Returns:boolean whether a match found or not

columnMatchFound

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private boolean columnMatchFound(ResultSetNode target, ColumnReference crOfExpression) throws StandardException

This method checks a ColumnReference of this OrderByColumn against the ColumnReferences of the select clause of the query.

Parameters

target:ResultSetNode: result set
crOfExpression:ColumnReference: the CR to be checked

Returns:boolean

whether a match found or not

constantColumn	back to summary
pack-priv boolean constantColumn(PredicateList whereClause) Is this OrderByColumn constant, according to the given predicate list? A constant column is one where all the column references it uses are compared equal to constants.

expressionMatch	back to summary
private boolean expressionMatch(ResultSetNode target) throws StandardException Checks whether the whole expression (OrderByColumn) itself found in the select clause. Parameters target:ResultSetNode Result set Returns:boolean boolean: whether any expression match found

expressionMatch

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private boolean expressionMatch(ResultSetNode target) throws StandardException

Checks whether the whole expression (OrderByColumn) itself found in the select clause.

Parameters

target:ResultSetNode: Result set

Returns:boolean

boolean: whether any expression match found

getExpression	back to summary
pack-priv ValueNode getExpression()

getNonRedundantExpression	back to summary
pack-priv ValueNode getNonRedundantExpression() Get the underlying expression, skipping over ResultColumns that are marked redundant.

getResultColumn	back to summary
pack-priv ResultColumn getResultColumn() Get the underlying ResultColumn. Returns:ResultColumn The underlying ResultColumn.

getResultColumn

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pack-priv ResultColumn getResultColumn()

Get the underlying ResultColumn.

Returns:ResultColumn: The underlying ResultColumn.

isAscending	back to summary
pack-priv boolean isAscending() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isAscending. Get the column order. Overrides OrderedColumn.isAscending. Returns:boolean true if ascending, false if descending Annotations @Override

isAscending

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pack-priv boolean isAscending()

Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isAscending.

Get the column order. Overrides OrderedColumn.isAscending.

Returns:boolean

true if ascending, false if descending

Annotations

@Override

isNullsOrderedLow	back to summary
pack-priv boolean isNullsOrderedLow() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isNullsOrderedLow. Get the column NULL ordering. Overrides OrderedColumn.getIsNullsOrderedLow. Returns:boolean true if NULLs ordered low, false if NULLs ordered high Annotations @Override

isNullsOrderedLow

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pack-priv boolean isNullsOrderedLow()

Overrides org.apache.derby.impl.sql.compile.OrderedColumn.isNullsOrderedLow.

Get the column NULL ordering. Overrides OrderedColumn.getIsNullsOrderedLow.

Returns:boolean

true if NULLs ordered low, false if NULLs ordered high

Annotations

@Override

isReferedColByNum	back to summary
private static boolean isReferedColByNum(ValueNode expression) throws StandardException

printSubNodes	back to summary
pack-priv void printSubNodes(int depth) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes. Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work. Parameters depth:int The depth of this node in the tree Annotations @Override

printSubNodes

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pack-priv void printSubNodes(int depth)

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes.

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Parameters

depth:int: The depth of this node in the tree

Annotations

@Override

pullUpOrderByColumn	back to summary
pack-priv void pullUpOrderByColumn(ResultSetNode target) throws StandardException Pull up this orderby column if it doesn't appear in the resultset Parameters target:ResultSetNode The result set being selected from

pullUpOrderByColumn

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pack-priv void pullUpOrderByColumn(ResultSetNode target) throws StandardException

Pull up this orderby column if it doesn't appear in the resultset

Parameters

target:ResultSetNode: The result set being selected from

remapColumnReferencesToExpressions	back to summary
pack-priv void remapColumnReferencesToExpressions() throws StandardException Remap all the column references under this OrderByColumn to their expressions. Exceptions StandardException: Thrown on error

remapColumnReferencesToExpressions

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pack-priv void remapColumnReferencesToExpressions() throws StandardException

Remap all the column references under this OrderByColumn to their expressions.

Exceptions

StandardException:: Thrown on error

resetToSourceRC	back to summary
pack-priv void resetToSourceRC() Order by columns now point to the PRN above the node of interest. We need them to point to the RCL under that one. This is useful when combining sorts where we need to reorder the sorting columns.

resolveAddedColumn	back to summary
private void resolveAddedColumn(ResultSetNode target) Assuming this OrderByColumn was "pulled" into the received target's ResultColumnList (because it wasn't there to begin with), use this.addedColumnOffset to figure out which of the target's result columns is the one corresponding to "this". The desired position is w.r.t. the original, user-specified result column list--which is what "visibleSize()" gives us. I.e. To get this OrderByColumn's position in target's RCL, first subtract out all columns which were "pulled" into the RCL for GROUP BY or ORDER BY, then add "this.addedColumnOffset". As an example, if the query was: select sum(j) as s from t1 group by i, k order by k, sum(k) then we will internally add columns "K" and "SUM(K)" to the RCL for ORDER BY, AND we will add a generated column "I" to the RCL for GROUP BY. Thus we end up with four result columns: (1) (2) (3) (4) select sum(j) as s, K, SUM(K), I from t1 ... So when we get here and we want to find out which column "this" corresponds to, we begin by taking the total number of VISIBLE columns, which is 1 (i.e. 4 total columns minus 1 GROUP BY column minus 2 ORDER BY columns). Then we add this.addedColumnOffset in order to find the target column position. Since addedColumnOffset is 0-based, an addedColumnOffset value of "0" means we want the the first ORDER BY column added to target's RCL, "1" means we want the second ORDER BY column added, etc. So if we assume that this.addedColumnOffset is "1" in this example then we add that to the RCL's "visible size". And finally, we add 1 more to account for fact that addedColumnOffset is 0-based while column positions are 1-based. This gives: position = 1 + 1 + 1 = 3 which points to SUM(K) in the RCL. Thus an addedColumnOffset value of "1" resolves to column SUM(K) in target's RCL; similarly, an addedColumnOffset value of "0" resolves to "K". DERBY-3303.

resolveAddedColumn

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private void resolveAddedColumn(ResultSetNode target)

Assuming this OrderByColumn was "pulled" into the received target's ResultColumnList (because it wasn't there to begin with), use this.addedColumnOffset to figure out which of the target's result columns is the one corresponding to "this". The desired position is w.r.t. the original, user-specified result column list--which is what "visibleSize()" gives us. I.e. To get this OrderByColumn's position in target's RCL, first subtract out all columns which were "pulled" into the RCL for GROUP BY or ORDER BY, then add "this.addedColumnOffset". As an example, if the query was: select sum(j) as s from t1 group by i, k order by k, sum(k) then we will internally add columns "K" and "SUM(K)" to the RCL for ORDER BY, *AND* we will add a generated column "I" to the RCL for GROUP BY. Thus we end up with four result columns: (1) (2) (3) (4) select sum(j) as s, K, SUM(K), I from t1 ... So when we get here and we want to find out which column "this" corresponds to, we begin by taking the total number of VISIBLE columns, which is 1 (i.e. 4 total columns minus 1 GROUP BY column minus 2 ORDER BY columns). Then we add this.addedColumnOffset in order to find the target column position. Since addedColumnOffset is 0-based, an addedColumnOffset value of "0" means we want the the first ORDER BY column added to target's RCL, "1" means we want the second ORDER BY column added, etc. So if we assume that this.addedColumnOffset is "1" in this example then we add that to the RCL's "visible size". And finally, we add 1 more to account for fact that addedColumnOffset is 0-based while column positions are 1-based. This gives: position = 1 + 1 + 1 = 3 which points to SUM(K) in the RCL. Thus an addedColumnOffset value of "1" resolves to column SUM(K) in target's RCL; similarly, an addedColumnOffset value of "0" resolves to "K". DERBY-3303.

resolveColumnReference	back to summary
private ResultColumn resolveColumnReference(ResultSetNode target, ColumnReference cr) throws StandardException

setDescending	back to summary
pack-priv void setDescending() Mark the column as descending order

setNullsOrderedLow	back to summary
pack-priv void setNullsOrderedLow() Mark the column as ordered NULL values lower than non-NULL values.

toString	back to summary
public String toString() Overrides org.apache.derby.impl.sql.compile.OrderedColumn.toString. Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing. Returns:String This object as a String Annotations @Override

toString

back to summary

public String toString()

Overrides org.apache.derby.impl.sql.compile.OrderedColumn.toString.

Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Returns:String

This object as a String

Annotations

@Override

pack-priv Class OrderByColumn

Field Summary

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Method Summary

Field Detail

Constructor Detail

Method Detail