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

Modifier and Type	Field and Description
pack-priv int	columnId
private boolean	correlated
private ResultColumn	sourceColumn
private ResultSetNode	sourceResultSet

Access	Constructor and Description
pack-priv	VirtualColumnNode(ResultSetNode The ResultSetNode where the value is originating sourceResultSet, ResultColumn The ResultColumn where the value is originating sourceColumn, int The columnId within the current Row columnId, ContextManager The context manager cm) Constructor for a VirtualColumnNode.

Method Summary

Modifier and Type	Method and Description
pack-priv void	generateExpression(ExpressionClassBuilder The ExpressionClassBuilder for the class being built acb, MethodBuilder The method the expression will go into mb) Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression. ColumnNode's are against the current row in the system.
pack-priv boolean	Returns: Whether or not this VCN is a correlated reference. getCorrelated() Return whether or not this VCN is a correlated reference.
protected int	Returns: The variant type for the underlying expression. getOrderableVariantType() Overrides org.apache.derby.impl.sql.compile.ValueNode.getOrderableVariantType. Return the variant type for the underlying expression.
pack-priv String	Returns: A String containing the name of the schema for the Column's table. If the column is not in a schema (i.e. derived column), it returns NULL. getSchemaName() Overrides org.apache.derby.impl.sql.compile.ValueNode.getSchemaName. Get the name of the schema the ResultColumn's table is in, if any.
pack-priv ResultColumn	Returns: ResultSetNode getSourceColumn() Return the ResultColumn that is the source of this VirtualColumnNode.
pack-priv ResultColumn	Returns: ResultSetNode getSourceResultColumn() Overrides org.apache.derby.impl.sql.compile.ValueNode.getSourceResultColumn. Return the ResultColumn that is the source of this VirtualColumnNode.
pack-priv ResultSetNode	Returns: ResultSetNode getSourceResultSet() Return the ResultSetNode that is the source of this VirtualColumnNode.
pack-priv String	Returns: A String containing the name of the table the Column is in. If the column is not in a table (i.e. is a derived column), it returns NULL. getTableName() Overrides org.apache.derby.impl.sql.compile.ValueNode.getTableName. Get the name of the table the ResultColumn is in, if any.
public final DataTypeDescriptor	Returns: The DataTypeServices from this Node. This may be null if the node isn't bound yet. getTypeServices() Overrides org.apache.derby.impl.sql.compile.ValueNode.getTypeServices. Get the DataTypeServices from this Node.
pack-priv boolean	Returns: boolean Whether or not this expression tree is cloneable. isCloneable() Overrides org.apache.derby.impl.sql.compile.ValueNode.isCloneable. Return whether or not this expression tree is cloneable.
pack-priv boolean	isEquivalent(ValueNode the node to compare this ValueNode against. o) Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. Tests if this node is equivalent to the specified ValueNode.
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	setCorrelated() Mark this VCN as a reference to a correlated column.
public final void	setType(DataTypeDescriptor The DataTypeServices to set in this ValueNode dtd) Overrides org.apache.derby.impl.sql.compile.ValueNode.setType. Set the DataTypeServices for this ValueNode.
public boolean	Returns: TRUE, if the column is a base column of a table and is writable by a positioned update. updatableByCursor() Overrides org.apache.derby.impl.sql.compile.ValueNode.updatableByCursor. Return whether or not the ResultColumn is wirtable by a positioned update.

Inherited from org.apache.derby.impl.sql.compile.ValueNode:: bindExpression bindExpression categorize changeToCNF checkIsBoolean checkTopPredicatesForEqualsConditions constantExpression copyFields eliminateNots evaluateConstantExpressions genEqualsFalseTree generate genIsNullTree genSQLJavaSQLTree getClone getColumnName getConstantValueAsObject getDataValueFactory getTablesReferenced getTransformed getTypeCompiler getTypeId isBinaryEqualsOperatorNode isBooleanFalse isBooleanTrue isConstantExpression isInListProbeNode isParameterNode isRelationalOperator isSameNodeKind optimizableEqualityNode preprocess putAndsOnTop remapColumnReferencesToExpressions requiresTypeFromContext selectivity setCollationInfo setCollationInfo setCollationUsingCompilationSchema setCollationUsingCompilationSchema setNullability setTransformed setType setType toString verifyChangeToCNF verifyEliminateNots verifyPutAndsOnTop

columnId	back to summary
pack-priv int columnId

correlated	back to summary
private boolean correlated

sourceColumn	back to summary
private ResultColumn sourceColumn

sourceResultSet	back to summary
private ResultSetNode sourceResultSet

VirtualColumnNode	back to summary
pack-priv VirtualColumnNode(ResultSetNode sourceResultSet, ResultColumn sourceColumn, int columnId, ContextManager cm) throws StandardException Constructor for a VirtualColumnNode. Parameters sourceResultSet:ResultSetNode The ResultSetNode where the value is originating sourceColumn:ResultColumn The ResultColumn where the value is originating columnId:int The columnId within the current Row cm:ContextManager The context manager

Method Detail

generateExpression	back to summary
pack-priv void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression. ColumnNode's are against the current row in the system. This lets us generate a faster get that simply returns the column from the current row, rather than getting the value out and returning that, only to have the caller (in the situations needed) stuffing it back into a new column holder object. We will assume the general generate() path is for getting the value out, and use generateColumn() when we want to keep the column wrapped. Parameters acb:ExpressionClassBuilder Doc from org.apache.derby.impl.sql.compile.ValueNode.generateExpression. The ExpressionClassBuilder for the class being built mb:MethodBuilder Doc from org.apache.derby.impl.sql.compile.ValueNode.generateExpression. The method the expression will go into Annotations @Override Exceptions StandardException: Thrown on error

generateExpression

back to summary

pack-priv void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression.

ColumnNode's are against the current row in the system. This lets us generate a faster get that simply returns the column from the current row, rather than getting the value out and returning that, only to have the caller (in the situations needed) stuffing it back into a new column holder object. We will assume the general generate() path is for getting the value out, and use generateColumn() when we want to keep the column wrapped.

Parameters

acb:ExpressionClassBuilder

Doc from org.apache.derby.impl.sql.compile.ValueNode.generateExpression.

The ExpressionClassBuilder for the class being built

mb:MethodBuilder

Doc from org.apache.derby.impl.sql.compile.ValueNode.generateExpression.

The method the expression will go into

Annotations

@Override

Exceptions

StandardException:: Thrown on error

getCorrelated	back to summary
pack-priv boolean getCorrelated() Return whether or not this VCN is a correlated reference. Returns:boolean Whether or not this VCN is a correlated reference.

getCorrelated

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pack-priv boolean getCorrelated()

Return whether or not this VCN is a correlated reference.

Returns:boolean: Whether or not this VCN is a correlated reference.

getOrderableVariantType	back to summary
protected int getOrderableVariantType() throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.getOrderableVariantType. Return the variant type for the underlying expression. The variant type can be: VARIANT - variant within a scan (method calls and non-static field access) SCAN_INVARIANT - invariant within a scan (column references from outer tables) QUERY_INVARIANT - invariant within the life of a query (constant expressions) Returns:int The variant type for the underlying expression. Annotations @Override Exceptions StandardException: thrown on error

getOrderableVariantType

back to summary

protected int getOrderableVariantType() throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.getOrderableVariantType.

Return the variant type for the underlying expression. The variant type can be: VARIANT - variant within a scan (method calls and non-static field access) SCAN_INVARIANT - invariant within a scan (column references from outer tables) QUERY_INVARIANT - invariant within the life of a query (constant expressions)

Returns:int

The variant type for the underlying expression.

Annotations

@Override

Exceptions

StandardException:: thrown on error

getSchemaName	back to summary
pack-priv String getSchemaName() throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.getSchemaName. Get the name of the schema the ResultColumn's table is in, if any. The return value will be null if the user did not supply a schema name (for example, select t.a from t). Another example for null return value (for example, select b.a from t as b). But for following query select app.t.a from t, this will return APP Returns:String A String containing the name of the schema for the Column's table. If the column is not in a schema (i.e. derived column), it returns NULL. Annotations @Override

getSchemaName

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pack-priv String getSchemaName() throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.getSchemaName.

Get the name of the schema the ResultColumn's table is in, if any. The return value will be null if the user did not supply a schema name (for example, select t.a from t). Another example for null return value (for example, select b.a from t as b). But for following query select app.t.a from t, this will return APP

Returns:String

A String containing the name of the schema for the Column's table. If the column is not in a schema (i.e. derived column), it returns NULL.

Annotations

@Override

getSourceColumn	back to summary
pack-priv ResultColumn getSourceColumn() Return the ResultColumn that is the source of this VirtualColumnNode. Returns:ResultColumn ResultSetNode

getSourceColumn

back to summary

pack-priv ResultColumn getSourceColumn()

Return the ResultColumn that is the source of this VirtualColumnNode.

Returns:ResultColumn: ResultSetNode

getSourceResultColumn	back to summary
pack-priv ResultColumn getSourceResultColumn() Overrides org.apache.derby.impl.sql.compile.ValueNode.getSourceResultColumn. Return the ResultColumn that is the source of this VirtualColumnNode. Returns:ResultColumn ResultSetNode Annotations @Override

getSourceResultColumn

back to summary

pack-priv ResultColumn getSourceResultColumn()

Overrides org.apache.derby.impl.sql.compile.ValueNode.getSourceResultColumn.

Return the ResultColumn that is the source of this VirtualColumnNode.

Returns:ResultColumn

ResultSetNode

Annotations

@Override

getSourceResultSet	back to summary
pack-priv ResultSetNode getSourceResultSet() Return the ResultSetNode that is the source of this VirtualColumnNode. Returns:ResultSetNode ResultSetNode

getSourceResultSet

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pack-priv ResultSetNode getSourceResultSet()

Return the ResultSetNode that is the source of this VirtualColumnNode.

Returns:ResultSetNode: ResultSetNode

getTableName	back to summary
pack-priv String getTableName() Overrides org.apache.derby.impl.sql.compile.ValueNode.getTableName. Get the name of the table the ResultColumn is in, if any. This will be null if the user did not supply a name (for example, select a from t). The method will return B for this example, select b.a from t as b The method will return T for this example, select t.a from t Returns:String A String containing the name of the table the Column is in. If the column is not in a table (i.e. is a derived column), it returns NULL. Annotations @Override

getTableName

back to summary

pack-priv String getTableName()

Overrides org.apache.derby.impl.sql.compile.ValueNode.getTableName.

Get the name of the table the ResultColumn is in, if any. This will be null if the user did not supply a name (for example, select a from t). The method will return B for this example, select b.a from t as b The method will return T for this example, select t.a from t

Returns:String

A String containing the name of the table the Column is in. If the column is not in a table (i.e. is a derived column), it returns NULL.

Annotations

@Override

getTypeServices	back to summary
public final DataTypeDescriptor getTypeServices() Overrides org.apache.derby.impl.sql.compile.ValueNode.getTypeServices. Get the DataTypeServices from this Node. Returns:DataTypeDescriptor The DataTypeServices from this Node. This may be null if the node isn't bound yet. Annotations @Override

getTypeServices

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public final DataTypeDescriptor getTypeServices()

Overrides org.apache.derby.impl.sql.compile.ValueNode.getTypeServices.

Get the DataTypeServices from this Node.

Returns:DataTypeDescriptor

The DataTypeServices from this Node. This may be null if the node isn't bound yet.

Annotations

@Override

isCloneable	back to summary
pack-priv boolean isCloneable() Overrides org.apache.derby.impl.sql.compile.ValueNode.isCloneable. Return whether or not this expression tree is cloneable. Returns:boolean boolean Whether or not this expression tree is cloneable. Annotations @Override

isCloneable

back to summary

pack-priv boolean isCloneable()

Overrides org.apache.derby.impl.sql.compile.ValueNode.isCloneable.

Return whether or not this expression tree is cloneable.

Returns:boolean

boolean Whether or not this expression tree is cloneable.

Annotations

@Override

isEquivalent back to summary

isEquivalent	back to summary
pack-priv boolean isEquivalent(ValueNode o) throws StandardException Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. Doc from org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution. This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase. Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown. One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.: SELECT c1+c2 FROM t1 GROUP BY c1+c2 In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below: The two ValueNodes must be of the same node type to be considered equivalent. e.g.: CastNode vs. CastNode - equivalent (if their args also match), ColumnReference vs CastNode - not equivalent. If node P contains other ValueNode(s) and so on, those node(s) must also be of the same node type to be considered equivalent. If node P takes a parameter list, then the number of arguments and its arguments for the two nodes must also match to be considered equivalent. e.g.: CAST(c1 as INTEGER) vs CAST(c1 as SMALLINT), they are not equivalent. When comparing SQL NULLs in this context, they are considered to be equivalent. If this does not apply or it is determined that the two nodes are not equivalent then the derived class of this method should return false; otherwise, return true. Parameters o:ValueNode the node to compare this ValueNode against. Returns:boolean `true` if the two nodes are equivalent, `false` otherwise.

pack-priv boolean isEquivalent(ValueNode o) throws StandardException

Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

Doc from org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution.

This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.

Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.

One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:

SELECT c1+c2 FROM t1 GROUP BY c1+c2

In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:

The two ValueNodes must be of the same node type to be considered equivalent. e.g.: CastNode vs. CastNode - equivalent (if their args also match), ColumnReference vs CastNode - not equivalent.
If node P contains other ValueNode(s) and so on, those node(s) must also be of the same node type to be considered equivalent.
If node P takes a parameter list, then the number of arguments and its arguments for the two nodes must also match to be considered equivalent. e.g.: CAST(c1 as INTEGER) vs CAST(c1 as SMALLINT), they are not equivalent.
When comparing SQL NULLs in this context, they are considered to be equivalent.
If this does not apply or it is determined that the two nodes are not equivalent then the derived class of this method should return false; otherwise, return true.

Parameters

o:ValueNode: the node to compare this ValueNode against.

Returns:boolean

true if the two nodes are equivalent, false otherwise.

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

setCorrelated	back to summary
pack-priv void setCorrelated() Mark this VCN as a reference to a correlated column. (It's source resultSet is an outer ResultSet.

setType	back to summary
public final void setType(DataTypeDescriptor dtd) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.setType. Doc from org.apache.derby.impl.sql.compile.ValueNode.setType. Set the DataTypeServices for this ValueNode. This method is overridden in ParameterNode. Parameters dtd:DataTypeDescriptor The DataTypeServices to set in this ValueNode Annotations @Override

setType

back to summary

public final void setType(DataTypeDescriptor dtd) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.setType.

Doc from org.apache.derby.impl.sql.compile.ValueNode.setType.

Set the DataTypeServices for this ValueNode. This method is overridden in ParameterNode.

Parameters

dtd:DataTypeDescriptor: The DataTypeServices to set in this ValueNode

Annotations

@Override

updatableByCursor	back to summary
public boolean updatableByCursor() Overrides org.apache.derby.impl.sql.compile.ValueNode.updatableByCursor. Return whether or not the ResultColumn is wirtable by a positioned update. Returns:boolean TRUE, if the column is a base column of a table and is writable by a positioned update. Annotations @Override

updatableByCursor

back to summary

public boolean updatableByCursor()

Overrides org.apache.derby.impl.sql.compile.ValueNode.updatableByCursor.

Return whether or not the ResultColumn is wirtable by a positioned update.

Returns:boolean

TRUE, if the column is a base column of a table and is writable by a positioned update.

Annotations

@Override

pack-priv Class VirtualColumnNode

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