DeleteNode (Apache Derby V10.14 Internals)

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:

Visitable
```
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

Fields
Modifier and Type	Field	Description
`private boolean`	`cascadeDelete`
`private static java.lang.String`	`COLUMNNAME`
`private boolean`	`deferred`
`private ConstantAction[]`	`dependentConstantActions`
`private StatementNode[]`	`dependentNodes`
`private FormatableBitSet`	`readColsBitSet`
`private FromTable`	`targetTable`

Fields inherited from class org.apache.derby.impl.sql.compile.DMLModStatementNode
dependentTables, fkColArrays, fkColDescriptors, fkIndexConglomNumbers, fkInfo, fkRefActions, fkSchemaNames, fkTableNames, indexConglomerateNumbers, indexNames, indicesToMaintain, isDependentTable, lockMode, matchingClause, 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.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

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

Constructor Summary

Constructors
Constructor	Description
`DeleteNode(TableName targetTableName, ResultSetNode queryExpression, MatchingClauseNode matchingClause, ContextManager cm)`	Constructor for a DeleteNode.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`bindStatement()`	Bind this DeleteNode.
`private void`	`correlateAddedColumns(ResultColumnList rcl, FromTable fromTable)`
`(package private) void`	`generate(ActivationClassBuilder acb, MethodBuilder mb)`	Code generation for delete.
`private static FormatableBitSet`	`getDeleteReadMap(TableDescriptor baseTable, java.util.List<ConglomerateDescriptor> conglomerates, TriggerDescriptorList 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 schemaName, 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(ColumnDescriptorList cdl)`
`protected int`	`getStatementType()`	Return the type of statement, something from StatementType.
`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)
`(package private) java.lang.String`	`statementToString()`

Methods inherited from class org.apache.derby.impl.sql.compile.DMLStatementNode
activationKind, bind, bindExpressions, bindExpressionsWithTables, bindResultSetsWithTables, bindTables, generateParameterValueSet, getResultSetNode, makeResultDescription

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from class org.apache.derby.impl.sql.compile.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, getTableDescriptor, getTypeCompiler, getUDTDesc, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, resolveTableToSynonym, setBeginOffset, setEndOffset, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class org.apache.derby.impl.sql.compile.StatementNode
executeSchemaName, executeStatementName, generate, getCursorInfo, getSPSName, lockTableForCompilation, needsSavepoint, toString, updateIndexStatisticsFor

- Field Detail
  - COLUMNNAME
```
private static final java.lang.String COLUMNNAME
```
    See Also:
    
    Constant Field Values
  - deferred
```
private boolean deferred
```
  - targetTable
```
private FromTable targetTable
```
  - readColsBitSet
```
private FormatableBitSet readColsBitSet
```
  - dependentConstantActions
```
private ConstantAction[] dependentConstantActions
```
  - cascadeDelete
```
private boolean cascadeDelete
```
  - dependentNodes
```
private StatementNode[] dependentNodes
```
- Constructor Detail
  - DeleteNode
```
DeleteNode(TableName targetTableName,
           ResultSetNode queryExpression,
           MatchingClauseNode matchingClause,
           ContextManager cm)
```
    Constructor for a DeleteNode.
    
    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
    
    matchingClause - Non-null if this DML is part of a MATCHED clause of a MERGE statement.
    
    cm - The context manager
- Method Detail
  - statementToString
```
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
```
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 schemaName,
                                            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(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<ConglomerateDescriptor> conglomerates,
                                                 TriggerDescriptorList 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:
    
    conglomerates - OUT: list 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

Class DeleteNode

Field Summary

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

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

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

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

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

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

Field Detail

COLUMNNAME

deferred

targetTable

readColsBitSet

dependentConstantActions

cascadeDelete

dependentNodes

Constructor Detail

DeleteNode

Method Detail

statementToString

bindStatement

getPrivType

referencesSessionSchema

makeConstantAction

generate

getStatementType

getReadMap

getDependentTableNode

getEmptyDeleteNode

getEmptyUpdateNode

getSetClause

optimizeStatement

getDeleteReadMap

correlateAddedColumns