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

Modifier and Type	Field and Description
pack-priv DataValueDescriptor	value

Access	Constructor and Description
pack-priv	ConstantNode(TypeId typeId, boolean nullable, int maximumWidth, ContextManager cm)
pack-priv	ConstantNode(ContextManager cm)

Method Summary

Modifier and Type	Method and Description
pack-priv ValueNode	Returns: The new top of the expression tree. bindExpression(FromList The FROM list for the query this expression is in, for binding columns. fromList, SubqueryList The subquery list being built as we find SubqueryNodes subqueryList, List<AggregateNode> The aggregate list being built as we find AggregateNodes aggregates) Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression. Bind this expression.
pack-priv boolean	constantExpression(PredicateList whereClause) Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression. Return whether or not this expression tree represents a constant value.
pack-priv abstract void	generateConstant(ExpressionClassBuilder The ExpressionClassBuilder for the class being built acb, MethodBuilder The method the code to place the code mb) This generates the proper constant.
pack-priv void	generateExpression(ExpressionClassBuilder The ExpressionClassBuilder for the class being built acb, MethodBuilder The method the code to place the code mb) Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression. For a ConstantNode, we generate the equivalent literal value.
pack-priv ValueNode	Returns: ValueNode A clone of this node. getClone() Overrides org.apache.derby.impl.sql.compile.ValueNode.getClone. Return a clone of this node.
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 DataValueDescriptor	getValue() Get the value in this ConstantNode
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	Returns: Whether or not this expression tree represents a constant expression. isConstantExpression() Overrides org.apache.derby.impl.sql.compile.ValueNode.isConstantExpression. Return whether or not this expression tree represents a constant expression.
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 boolean	isNull() Return whether or not this node represents a typed null constant.
pack-priv void	setValue(DataValueDescriptor value) Set the value in this ConstantNode.
public String	Returns: This object as a String toString() Overrides org.apache.derby.impl.sql.compile.ValueNode.toString. Convert this object to a String.

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

value	back to summary
pack-priv DataValueDescriptor value

ConstantNode	back to summary
pack-priv ConstantNode(TypeId typeId, boolean nullable, int maximumWidth, ContextManager cm) throws StandardException

ConstantNode	back to summary
pack-priv ConstantNode(ContextManager cm)

Method Detail

bindExpression	back to summary
pack-priv ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression. Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. In this case, there are no sub-expressions, and the return type is already known, so this is just a stub. Parameters fromList:FromList The FROM list for the query this expression is in, for binding columns. subqueryList:SubqueryList The subquery list being built as we find SubqueryNodes aggregates:List<AggregateNode> The aggregate list being built as we find AggregateNodes Returns:ValueNode The new top of the expression tree. Annotations @Override Exceptions StandardException: Thrown on error. Although this class doesn't throw this exception, it's subclasses do and hence this method signature here needs to have throws StandardException

bindExpression

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pack-priv ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException

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

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. In this case, there are no sub-expressions, and the return type is already known, so this is just a stub.

Parameters

fromList:FromList: The FROM list for the query this expression is in, for binding columns.
subqueryList:SubqueryList: The subquery list being built as we find SubqueryNodes
aggregates:List<AggregateNode>: The aggregate list being built as we find AggregateNodes

Returns:ValueNode

The new top of the expression tree.

Annotations

@Override

Exceptions

StandardException:: Thrown on error. Although this class doesn't throw this exception, it's subclasses do and hence this method signature here needs to have throws StandardException

constantExpression back to summary

constantExpression	back to summary
pack-priv boolean constantExpression(PredicateList whereClause) Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression. Doc from org.apache.derby.impl.sql.compile.ValueNode.constantExpression. Return whether or not this expression tree represents a constant value. In this case, "constant" means that it will always evaluate to the same thing, even if it includes columns. A column is constant if it is compared to a constant expression. Returns:boolean True means this expression tree represents a constant value. Annotations @Override See Also `ValueNode#constantExpression`

pack-priv boolean constantExpression(PredicateList whereClause)

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

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

Return whether or not this expression tree represents a constant value. In this case, "constant" means that it will always evaluate to the same thing, even if it includes columns. A column is constant if it is compared to a constant expression.

Returns:boolean

True means this expression tree represents a constant value.

Annotations

@Override

See Also

ValueNode#constantExpression

generateConstant	back to summary
pack-priv abstract void generateConstant(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException This generates the proper constant. It is implemented by every specific constant node (e.g. IntConstantNode). Parameters acb:ExpressionClassBuilder The ExpressionClassBuilder for the class being built mb:MethodBuilder The method the code to place the code Exceptions StandardException: Thrown on error

generateConstant

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

This generates the proper constant. It is implemented by every specific constant node (e.g. IntConstantNode).

Parameters

acb:ExpressionClassBuilder: The ExpressionClassBuilder for the class being built
mb:MethodBuilder: The method the code to place the code

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. For a ConstantNode, we generate the equivalent literal value. A null is generated as a Null value cast to the type of the constant node. The subtypes of ConstantNode generate literal expressions for non-null values. Parameters acb:ExpressionClassBuilder The ExpressionClassBuilder for the class being built mb:MethodBuilder The method the code to place the code Annotations @Override Exceptions StandardException: Thrown on error

generateExpression

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

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

For a ConstantNode, we generate the equivalent literal value. A null is generated as a Null value cast to the type of the constant node. The subtypes of ConstantNode generate literal expressions for non-null values.

Parameters

acb:ExpressionClassBuilder: The ExpressionClassBuilder for the class being built
mb:MethodBuilder: The method the code to place the code

Annotations

@Override

Exceptions

StandardException:: Thrown on error

getClone	back to summary
pack-priv ValueNode getClone() Overrides org.apache.derby.impl.sql.compile.ValueNode.getClone. Return a clone of this node. Returns:ValueNode ValueNode A clone of this node. Annotations @Override

getClone

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pack-priv ValueNode getClone()

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

Return a clone of this node.

Returns:ValueNode

ValueNode A clone of this node.

Annotations

@Override

getOrderableVariantType	back to summary
protected int getOrderableVariantType() 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 VARIANT - immutable Returns:int The variant type for the underlying expression. Annotations @Override

getOrderableVariantType

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protected int getOrderableVariantType()

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 VARIANT - immutable

Returns:int

The variant type for the underlying expression.

Annotations

@Override

getValue	back to summary
pack-priv DataValueDescriptor getValue() Get the value in this ConstantNode

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

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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

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

isConstantExpression

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pack-priv boolean isConstantExpression()

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

Return whether or not this expression tree represents a constant expression.

Returns:boolean

Whether or not this expression tree represents a constant expression.

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.

isNull	back to summary
pack-priv boolean isNull() Return whether or not this node represents a typed null constant.

setValue	back to summary
pack-priv void setValue(DataValueDescriptor value) Set the value in this ConstantNode.

toString	back to summary
public String toString() Overrides org.apache.derby.impl.sql.compile.ValueNode.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

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public String toString()

Overrides org.apache.derby.impl.sql.compile.ValueNode.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 abstract Class ConstantNode

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