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org.apache.derby.impl.sql.compile
Class SpecialFunctionNode  

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ValueNode
          org.apache.derby.impl.sql.compile.SpecialFunctionNode

All Implemented Interfaces:

org.apache.derby.iapi.sql.compile.Visitable

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public class SpecialFunctionNode

extends ValueNode

SpecialFunctionNode handles system SQL functions. A function value is either obtained by a method call off the LanguageConnectionContext or Activation. LanguageConnectionContext functions are state related to the connection. Activation functions are those related to the statement execution. Each SQL function takes no arguments and returns a SQLvalue.

Functions supported:

• USER
• CURRENT_USER
• SESSION_USER
• SYSTEM_USER
• CURRENT SCHEMA
• CURRENT ISOLATION
• IDENTITY_VAL_LOCAL

This node is used rather than some use of MethodCallNode for runtime performance. MethodCallNode does not provide a fast access to the current language connection or activatation, since it is geared towards user defined routines.

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Field Summary
private  java.lang.String	methodName           Java method name
private  java.lang.String	methodType           Return type of Java method.
(package private)  java.lang.String	sqlName           Name of SQL function

 

Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode

clause, dataTypeServices, IN_HAVING_CLAUSE, IN_SELECT_LIST, IN_UNKNOWN_CLAUSE, IN_WHERE_CLAUSE, transformed

 

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, beginOffset, endOffset

 

Constructor Summary

SpecialFunctionNode()

 

Method Summary
ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector)           Binding this special function means setting the result DataTypeServices.
void	generateExpression(ExpressionClassBuilder acb, org.apache.derby.iapi.services.compiler.MethodBuilder mb)           Generate an expression that returns a DataValueDescriptor and calls a method off the language connection or the activation.
protected  int	getOrderableVariantType()           Return the variant type for the underlying expression.
java.lang.String	toString()           Convert this object to a String.

 

Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode

bindExpression, categorize, changeToCNF, checkIsBoolean, checkReliability, checkReliability, checkTopPredicatesForEqualsConditions, constantExpression, copyFields, eliminateNots, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClause, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isConstantExpression, isParameterNode, isRelationalOperator, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, selectivity, setClause, setDescriptor, setTransformed, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

 

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

accept, bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getSPSName, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeResultDescription, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, treePrint, treePrint, verifyClassExist

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Field Detail

sqlName

java.lang.String sqlName

Name of SQL function

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methodName

private java.lang.String methodName

Java method name

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methodType

private java.lang.String methodType

Return type of Java method.

Constructor Detail

SpecialFunctionNode

public SpecialFunctionNode()

Method Detail

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.Vector aggregateVector)
                         throws org.apache.derby.iapi.error.StandardException

Binding this special function means setting the result DataTypeServices. In this case, the result type is based on the operation requested.

Overrides:

bindExpression in class ValueNode

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getOrderableVariantType

protected int getOrderableVariantType()

Return the variant type for the underlying expression. All supported special functions are QUERY_INVARIANT

Overrides:

getOrderableVariantType in class ValueNode

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generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               org.apache.derby.iapi.services.compiler.MethodBuilder mb)
                        throws org.apache.derby.iapi.error.StandardException

Generate an expression that returns a DataValueDescriptor and calls a method off the language connection or the activation.

Overrides:

generateExpression in class ValueNode

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toString

public java.lang.String toString()

Description copied from class: ValueNode

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

Overrides:

toString in class ValueNode

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> sql >> [ compile overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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