Class NextSequenceNode

java.lang.Object

org.apache.derby.impl.sql.compile.QueryTreeNode

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

org.apache.derby.impl.sql.compile.NextSequenceNode

All Implemented Interfaces:

Visitable

class NextSequenceNode
extends ValueNode

A class that represents a value obtained from a Sequence using 'NEXT VALUE'

Field Summary

Fields

Modifier and Type	Field	Description
private SequenceDescriptor	sequenceDescriptor
private TableName	sequenceName

Fields inherited from class ValueNode

transformed

Fields inherited from class QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor	Description
NextSequenceNode(TableName sequenceName, ContextManager cm)	Constructor for a NextSequenceNode

Method Summary

Modifier and Type	Method	Description
(package private) void	acceptChildren(Visitor v)	Accept a visitor on all child nodes.
(package private) ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates, boolean forQueryRewrite)	Bind this expression.
(package private) void	generateConstant(ExpressionClassBuilder ecb, MethodBuilder mb)	Dummy implementation to return a constant.
(package private) void	generateExpression(ExpressionClassBuilder acb, MethodBuilder mb)	Generate code for this calculation.
(package private) boolean	isEquivalent(ValueNode other)	Tests if this node is equivalent to the specified ValueNode.
String	toString()	Convert this object to a String.

Methods inherited from class ValueNode

bindExpression, categorize, changeToCNF, checkIsBoolean, checkTopPredicatesForEqualsConditions, constantExpression, copyFields, eliminateNots, evaluateConstantExpressions, genEqualsFalseTree, generate, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getOrderableVariantType, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isConstantExpression, isInListProbeNode, isParameterNode, isRelationalOperator, isSameNodeKind, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, requiresTypeFromContext, selectivity, setCollationInfo, setCollationInfo, setCollationUsingCompilationSchema, setCollationUsingCompilationSchema, setNullability, setTransformed, setType, setType, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

Methods inherited from class QueryTreeNode

accept, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContext, getContextManager, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getLongProperty, getNullNode, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, getUDTDesc, isAtomic, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class Object

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

Field Details

sequenceName

private TableName sequenceName

sequenceDescriptor

private SequenceDescriptor sequenceDescriptor

Constructor Details

NextSequenceNode

NextSequenceNode(TableName sequenceName,
 ContextManager cm)

Constructor for a NextSequenceNode

Parameters:

sequenceName - The name of the sequence being called

cm - The context manager

Method Details

bindExpression

ValueNode bindExpression(FromList fromList,
 SubqueryList subqueryList,
 List<AggregateNode> aggregates,
 boolean forQueryRewrite)
                  throws StandardException

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression.

Overrides:

bindExpression in class ValueNode

Parameters:

fromList - The FROM list for the query this expression is in, for binding columns.

subqueryList - The subquery list being built as we find SubqueryNodes

aggregates - The aggregate list being built as we find AggregateNodes

Returns:

The new top of the expression tree.

Throws:

StandardException - Thrown on error

generateExpression

void generateExpression(ExpressionClassBuilder acb,
 MethodBuilder mb)
                 throws StandardException

Description copied from class: ValueNode

Generate code for this calculation. This is a place-holder method - it should not be called.

Overrides:

generateExpression in class ValueNode

Parameters:

acb - The ExpressionClassBuilder for the class being built

mb - The method the expression will go into

Throws:

StandardException - Thrown on error

generateConstant

void generateConstant(ExpressionClassBuilder ecb,
 MethodBuilder mb)
               throws StandardException

Dummy implementation to return a constant. Will be replaced with actual NEXT VALUE logic.

Parameters:

ecb - The ExpressionClassBuilder for the class being built

mb - The method the expression will go into

Throws:

StandardException - on error

toString

public String toString()

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

Returns:

This object as a String

isEquivalent

boolean isEquivalent(ValueNode other)
              throws StandardException

Description copied from class: ValueNode

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.

Specified by:

isEquivalent in class ValueNode

Parameters:

other - the node to compare this ValueNode against.

Returns:

true if the two nodes are equivalent, false otherwise.

Throws:

StandardException

acceptChildren

void acceptChildren(Visitor v)
             throws StandardException

Description copied from class: QueryTreeNode

Accept a visitor on all child nodes. All sub-classes that add fields that should be visited, should override this method and call accept(v) on all visitable fields, as well as super.acceptChildren(v) to make sure all visitable fields defined by the super-class are accepted too.

Overrides:

acceptChildren in class QueryTreeNode

Parameters:

v - the visitor

Throws:

StandardException - on errors raised by the visitor