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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.CurrentDatetimeOperatorNode
public class CurrentDatetimeOperatorNode
The CurrentDatetimeOperator operator is for the builtin CURRENT_DATE, CURRENT_TIME, and CURRENT_TIMESTAMP operations.
Field Summary | |
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static int |
CURRENT_DATE
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static int |
CURRENT_TIME
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static int |
CURRENT_TIMESTAMP
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private static int[] |
jdbcTypeId
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private static java.lang.String[] |
methodName
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private int |
whichType
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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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CurrentDatetimeOperatorNode()
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Method Summary | |
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ValueNode |
bindExpression(FromList fromList,
SubqueryList subqueryList,
java.util.Vector aggregateVector)
Binding this expression means setting the result DataTypeServices. |
void |
generateExpression(ExpressionClassBuilder acb,
MethodBuilder mb)
CurrentDatetimeOperatorNode is used in expressions. |
protected int |
getOrderableVariantType()
Return the variant type for the underlying expression. |
void |
init(java.lang.Object whichType)
Initialize a query tree node. |
protected boolean |
isEquivalent(ValueNode o)
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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public static final int CURRENT_DATE
public static final int CURRENT_TIME
public static final int CURRENT_TIMESTAMP
private static final int[] jdbcTypeId
private static final java.lang.String[] methodName
private int whichType
Constructor Detail |
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public CurrentDatetimeOperatorNode()
Method Detail |
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public void init(java.lang.Object whichType)
QueryTreeNode
init
in class QueryTreeNode
public ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector) throws StandardException
bindExpression
in class ValueNode
fromList
- The FROM list for the statement. This parameter
is not used in this case.subqueryList
- The subquery list being built as we find
SubqueryNodes. Not used in this case.aggregateVector
- The aggregate vector being built as we find
AggregateNodes. Not used in this case.
StandardException
- Thrown on errorprotected int getOrderableVariantType()
getOrderableVariantType
in class ValueNode
public void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException
generateExpression
in class ValueNode
acb
- The ExpressionClassBuilder for the class being builtmb
- The method the code to place the code
StandardException
- Thrown on errorpublic java.lang.String toString()
ValueNode
toString
in class ValueNode
protected boolean isEquivalent(ValueNode o)
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
o
- the node to compare this ValueNode against.
true
if the two nodes are equivalent,
false
otherwise.
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Built on Thu 2010-12-23 20:49:13+0000, from revision ??? | ||||||||
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