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

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.StatementNode
          org.apache.derby.impl.sql.compile.DMLStatementNode
              org.apache.derby.impl.sql.compile.DMLModStatementNode
                  org.apache.derby.impl.sql.compile.DeleteNode

All Implemented Interfaces:

Node, Visitable

public class DeleteNode
extends DMLModStatementNode

A DeleteNode represents a DELETE statement. It is the top-level node for the statement. For positioned delete, there may be no from table specified. The from table will be derived from the cursor specification of the named cursor.

Field Summary

private boolean	cascadeDelete
private static java.lang.String	COLUMNNAME
protected boolean	deferred
private ConstantAction[]	dependentConstantActions
private StatementNode[]	dependentNodes
protected FKInfo	fkInfo
protected FormatableBitSet	readColsBitSet
protected FromTable	targetTable

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

dependentTables, fkColArrays, fkColDescriptors, fkIndexConglomNumbers, fkRefActions, fkTableNames, indexConglomerateNumbers, indexNames, indicesToMaintain, isDependentTable, lockMode, relevantCdl, relevantTriggers, resultColumnList, synonymTableName, targetTableDescriptor, targetTableName, targetVTI, triggerInfo

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

resultSet

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

EMPTY_TD_LIST, NEED_CURSOR_ACTIVATION, NEED_DDL_ACTIVATION, NEED_NOTHING_ACTIVATION, NEED_PARAM_ACTIVATION, NEED_ROW_ACTIVATION

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

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, isPrivilegeCollectionRequired

Constructor Summary

DeleteNode()

Method Summary

void	bindStatement() Bind this DeleteNode.
private void	correlateAddedColumns(ResultColumnList rcl, FromTable fromTable)
void	generate(ActivationClassBuilder acb, MethodBuilder mb) Code generation for delete.
private static FormatableBitSet	getDeleteReadMap(TableDescriptor baseTable, java.util.List conglomVector, GenericDescriptorList relevantTriggers, boolean[] needsDeferredProcessing) Builds a bitmap of all columns which should be read from the Store in order to satisfy an DELETE statement. 1) finds all indices on this table 2) adds the index columns to a bitmap of affected columns 3) adds the index descriptors to a list of conglomerate descriptors. 4) finds all DELETE triggers on the table 5) if there are any DELETE triggers, then do one of the following a)If all of the triggers have MISSING referencing clause, then that means that the trigger actions do not have access to before and after values.
private StatementNode	getDependentTableNode(java.lang.String tableName, int refAction, ColumnDescriptorList cdl) In case of referential actions, we require to perform DML (UPDATE or DELETE) on the dependent tables.
private DeleteNode	getEmptyDeleteNode(java.lang.String schemaName, java.lang.String targetTableName)
private UpdateNode	getEmptyUpdateNode(java.lang.String schemaName, java.lang.String targetTableName, ColumnDescriptorList cdl)
(package private) int	getPrivType() Return default privilege needed for this node.
FormatableBitSet	getReadMap(DataDictionary dd, TableDescriptor baseTable) Gets the map of all columns which must be read out of the base table.
private ResultColumnList	getSetClause(TableName tabName, ColumnDescriptorList cdl)
protected int	getStatementType() Return the type of statement, something from StatementType.
void	init(java.lang.Object targetTableName, java.lang.Object queryExpression) Initializer for a DeleteNode.
ConstantAction	makeConstantAction() Compile constants that Execution will use
void	optimizeStatement() Generate an optimized QueryTree from a bound QueryTree.
boolean	referencesSessionSchema() Return true if the node references SESSION schema tables (temporary or permanent)
java.lang.String	statementToString()

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

acceptChildren, adjustDeferredFlag, bindConstraints, bindRowScopedExpression, generateCheckConstraints, generateCheckConstraints, generateCodeForTemporaryTable, generateGenerationClauses, getAffectedIndexes, getAllRelevantConstraints, getAllRelevantTriggers, getCheckConstraints, getFKInfo, getReadColMap, getResultColumnList, getResultColumnList, getSchemaDescriptor, getTriggerInfo, getXAffectedIndexes, hasCheckConstraints, hasGenerationClauses, init, isAtomic, markAffectedIndexes, normalizeSynonymColumns, parseAndBindGenerationClauses, parseCheckConstraint, parseGenerationClause, printSubNodes, requiresDeferredProcessing, setRefActionInfo, setTarget, verifyTargetTable

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

activationKind, bind, bindExpressions, bindExpressionsWithTables, bindResultSetsWithTables, bindTables, generateParameterValueSet, getResultSetNode, makeResultDescription

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

executeSchemaName, executeStatementName, generate, getSPSName, lockTableForCompilation, needsSavepoint, toString, updateIndexStatisticsFor

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

accept, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, stackPrint, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

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

Field Detail

COLUMNNAME

private static final java.lang.String COLUMNNAME

See Also:

Constant Field Values

deferred

protected boolean deferred

targetTable

protected FromTable targetTable

fkInfo

protected FKInfo fkInfo

readColsBitSet

protected FormatableBitSet readColsBitSet

dependentConstantActions

private ConstantAction[] dependentConstantActions

cascadeDelete

private boolean cascadeDelete

dependentNodes

private StatementNode[] dependentNodes

Constructor Detail

DeleteNode

public DeleteNode()

Method Detail

init

public void init(java.lang.Object targetTableName,
                 java.lang.Object queryExpression)

Initializer for a DeleteNode.

Specified by:

init in interface Node

Overrides:

init in class DMLModStatementNode

Parameters:

targetTableName - The name of the table to delete from

queryExpression - The query expression that will generate the rows to delete from the given table

statementToString

public java.lang.String statementToString()

Overrides:

statementToString in class DMLModStatementNode

bindStatement

public void bindStatement()
                   throws StandardException

Bind this DeleteNode. This means looking up tables and columns and getting their types, and figuring out the result types of all expressions, as well as doing view resolution, permissions checking, etc.

If any indexes need to be updated, we add all the columns in the base table to the result column list, so that we can use the column values as look-up keys for the index rows to be deleted. Binding a delete will also massage the tree so that the ResultSetNode has column containing the RowLocation of the base row.

Overrides:

bindStatement in class StatementNode

Throws:

StandardException - Thrown on error

getPrivType

int getPrivType()

Description copied from class: DMLStatementNode

Return default privilege needed for this node. Other DML nodes can override this method to set their own default privilege.

Overrides:

getPrivType in class DMLStatementNode

Returns:

true if the statement is atomic

referencesSessionSchema

public boolean referencesSessionSchema()
                                throws StandardException

Return true if the node references SESSION schema tables (temporary or permanent)

Overrides:

referencesSessionSchema in class QueryTreeNode

Returns:

true if references SESSION schema tables, else false

Throws:

StandardException - Thrown on error

makeConstantAction

public ConstantAction makeConstantAction()
                                  throws StandardException

Compile constants that Execution will use

Overrides:

makeConstantAction in class QueryTreeNode

Throws:

StandardException - Thrown on failure

generate

public void generate(ActivationClassBuilder acb,
                     MethodBuilder mb)
              throws StandardException

Code generation for delete. The generated code will contain: o A static member for the (xxx)ResultSet with the RowLocations o The static member will be assigned the appropriate ResultSet within the nested calls to get the ResultSets. (The appropriate cast to the (xxx)ResultSet will be generated.) o The CurrentRowLocation() in SelectNode's select list will generate a new method for returning the RowLocation as well as a call to that method which will be stuffed in the call to the ProjectRestrictResultSet. o In case of referential actions, this function generate an array of resultsets on its dependent tables.

Overrides:

generate in class QueryTreeNode

Parameters:

acb - The ActivationClassBuilder for the class being built

mb - The execute() method to be built

Throws:

StandardException - Thrown on error

getStatementType

protected final int getStatementType()

Return the type of statement, something from StatementType.

Overrides:

getStatementType in class QueryTreeNode

Returns:

the type of statement

getReadMap

public FormatableBitSet getReadMap(DataDictionary dd,
                                   TableDescriptor baseTable)
                            throws StandardException

Gets the map of all columns which must be read out of the base table. These are the columns needed to: o maintain indices o maintain foreign keys The returned map is a FormatableBitSet with 1 bit for each column in the table plus an extra, unsued 0-bit. If a 1-based column id must be read from the base table, then the corresponding 1-based bit is turned ON in the returned FormatableBitSet.

Parameters:

dd - the data dictionary to look in

baseTable - the base table descriptor

Returns:

a FormatableBitSet of columns to be read out of the base table

Throws:

StandardException - Thrown on error

getDependentTableNode

private StatementNode getDependentTableNode(java.lang.String tableName,
                                            int refAction,
                                            ColumnDescriptorList cdl)
                                     throws StandardException

In case of referential actions, we require to perform DML (UPDATE or DELETE) on the dependent tables. Following function returns the DML Node for the dependent table.

Throws:

StandardException

getEmptyDeleteNode

private DeleteNode getEmptyDeleteNode(java.lang.String schemaName,
                                      java.lang.String targetTableName)
                               throws StandardException

Throws:

StandardException

getEmptyUpdateNode

private UpdateNode getEmptyUpdateNode(java.lang.String schemaName,
                                      java.lang.String targetTableName,
                                      ColumnDescriptorList cdl)
                               throws StandardException

Throws:

StandardException

getSetClause

private ResultColumnList getSetClause(TableName tabName,
                                      ColumnDescriptorList cdl)
                               throws StandardException

Throws:

StandardException

optimizeStatement

public void optimizeStatement()
                       throws StandardException

Description copied from class: DMLModStatementNode

Generate an optimized QueryTree from a bound QueryTree. Actually, it can annotate the tree in place rather than generate a new tree, but this interface allows the root node of the optimized QueryTree to be different from the root node of the bound QueryTree. For non-optimizable statements, this method is a no-op. Throws an exception if the tree is not bound, or if the binding is out of date.

Overrides:

optimizeStatement in class DMLModStatementNode

Throws:

StandardException - Thrown on failure

getDeleteReadMap

private static FormatableBitSet getDeleteReadMap(TableDescriptor baseTable,
                                                 java.util.List conglomVector,
                                                 GenericDescriptorList relevantTriggers,
                                                 boolean[] needsDeferredProcessing)
                                          throws StandardException

Builds a bitmap of all columns which should be read from the Store in order to satisfy an DELETE statement. 1) finds all indices on this table 2) adds the index columns to a bitmap of affected columns 3) adds the index descriptors to a list of conglomerate descriptors. 4) finds all DELETE triggers on the table 5) if there are any DELETE triggers, then do one of the following a)If all of the triggers have MISSING referencing clause, then that means that the trigger actions do not have access to before and after values. In that case, there is no need to blanketly decide to include all the columns in the read map just because there are triggers defined on the table. b)Since one/more triggers have REFERENCING clause on them, get all the columns because we don't know what the user will ultimately reference. 6) adds the triggers to an evolving list of triggers

Parameters:

conglomVector - OUT: vector of affected indices

relevantTriggers - IN/OUT. Passed in as an empty list. Filled in as we go.

needsDeferredProcessing - IN/OUT. true if the statement already needs deferred processing. set while evaluating this routine if a trigger requires deferred processing

Returns:

a FormatableBitSet of columns to be read out of the base table

Throws:

StandardException - Thrown on error

correlateAddedColumns

private void correlateAddedColumns(ResultColumnList rcl,
                                   FromTable fromTable)
                            throws StandardException

Throws:

StandardException