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java.lang.Objectorg.apache.derby.impl.sql.compile.QueryTreeNode
org.apache.derby.impl.sql.compile.ValueNode
org.apache.derby.impl.sql.compile.NextSequenceNode
public class NextSequenceNode
A class that represents a value obtained from a Sequence using 'NEXT VALUE'
Field Summary | |
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private SequenceDescriptor |
sequenceDescriptor
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private TableName |
sequenceName
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Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode |
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transformed |
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode |
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AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired |
Constructor Summary | |
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NextSequenceNode()
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Method Summary | |
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ValueNode |
bindExpression(FromList fromList,
SubqueryList subqueryList,
java.util.Vector aggregateVector,
boolean forQueryRewrite)
Bind this expression. |
void |
generateConstant(ExpressionClassBuilder ecb,
MethodBuilder mb)
Dummy implementation to return a constant. |
void |
generateExpression(ExpressionClassBuilder acb,
MethodBuilder mb)
Generate code for this calculation. |
void |
init(java.lang.Object sequenceName)
Initializer for a NextSequenceNode |
protected boolean |
isEquivalent(ValueNode other)
Tests if this node is equivalent to the specified ValueNode. |
java.lang.String |
toString()
Convert this object to a String. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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private TableName sequenceName
private SequenceDescriptor sequenceDescriptor
Constructor Detail |
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public NextSequenceNode()
Method Detail |
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public void init(java.lang.Object sequenceName) throws StandardException
init
in class QueryTreeNode
sequenceName
- The name of the sequence being called
StandardException
- Thrown on errorpublic ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector, boolean forQueryRewrite) throws StandardException
bindExpression
in class ValueNode
fromList
- The FROM list for the query this
expression is in, for binding columns.subqueryList
- The subquery list being built as we find SubqueryNodesaggregateVector
- The aggregate vector being built as we find AggregateNodes
StandardException
- Thrown on errorpublic void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException
ValueNode
generateExpression
in class ValueNode
acb
- The ExpressionClassBuilder for the class being builtmb
- The method the expression will go into
StandardException
- Thrown on errorpublic void generateConstant(ExpressionClassBuilder ecb, MethodBuilder mb) throws StandardException
ecb
- The ExpressionClassBuilder for the class being builtmb
- The method the expression will go into
StandardException
- on errorpublic java.lang.String toString()
toString
in class ValueNode
protected boolean isEquivalent(ValueNode other) throws StandardException
ValueNode
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:
isEquivalent
in class ValueNode
other
- the node to compare this ValueNode against.
true
if the two nodes are equivalent,
false
otherwise.
StandardException
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Built on Thu 2012-03-29 21:53:33+0000, from revision ??? | ||||||||
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