org.apache.derby.impl.sql.compile

Class ModifyColumnNode

java.lang.Object

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

org.apache.derby.impl.sql.compile.TableElementNode

org.apache.derby.impl.sql.compile.ColumnDefinitionNode

org.apache.derby.impl.sql.compile.ModifyColumnNode

All Implemented Interfaces:

Node, Visitable

public class ModifyColumnNode
extends ColumnDefinitionNode

A ModifyColumnNode represents a modify column in an ALTER TABLE statement.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) int	columnPosition
(package private) UUID	oldDefaultUUID

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

autoinc_create_or_modify_Start_Increment, autoincrementIncrement, autoincrementStart, autoincrementVerify, CREATE_AUTOINCREMENT, defaultInfo, defaultNode, defaultValue, generationClauseNode, isAutoincrement, keepCurrentDefault, MODIFY_AUTOINCREMENT_INC_VALUE, MODIFY_AUTOINCREMENT_RESTART_VALUE, type

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

AT_ADD_CHECK_CONSTRAINT, AT_ADD_FOREIGN_KEY_CONSTRAINT, AT_ADD_PRIMARY_KEY_CONSTRAINT, AT_ADD_UNIQUE_CONSTRAINT, AT_DROP_COLUMN, AT_DROP_CONSTRAINT, AT_MODIFY_COLUMN, AT_UNKNOWN, elementType, name

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

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor and Description
ModifyColumnNode()

Method Summary

Methods

Modifier and Type	Method and Description
(package private) void	bindAndValidateDefault(DataDictionary dd, TableDescriptor td) Check the validity of the default, if any, for this node.
void	checkExistingConstraints(TableDescriptor td) Check if the the column can be modified, and throw error if not.
void	checkUserType(TableDescriptor td) Check the validity of a user type.
(package private) int	getAction() Get the action associated with this node.
int	getColumnPosition() Get the column position for the column.
private ColumnDescriptor	getLocalColumnDescriptor(java.lang.String name, TableDescriptor td)
(package private) UUID	getOldDefaultUUID() Get the UUID of the old column default.
void	useExistingCollation(TableDescriptor td) If the column being modified is of character string type, then it should get its collation from the corresponding column in the TableDescriptor.
void	validateAutoincrement(DataDictionary dd, TableDescriptor td, int tableType) check the validity of autoincrement values in the case that we are modifying an existing column (includes checking if autoincrement is set when making a column nullable)

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

defaultTypeIsValid, getAutoinc_create_or_modify_Start_Increment, getAutoincrementIncrement, getAutoincrementStart, getColumnName, getDefaultInfo, getDefaultNode, getDefaultValue, getGenerationClauseNode, getType, hasGenerationClause, init, isAutoincrementColumn, printSubNodes, setCollationType, setDefaultInfo, setNullability, setType, toString, validateDefault

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

getElementType, getName, hasCheckConstraint, hasConstraint, hasForeignKeyConstraint, hasPrimaryKeyConstraint, hasUniqueKeyConstraint, init, init

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

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

Methods inherited from class java.lang.Object

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

Field Detail

columnPosition

int columnPosition

oldDefaultUUID

UUID oldDefaultUUID

Constructor Detail

ModifyColumnNode

public ModifyColumnNode()

Method Detail

getOldDefaultUUID

UUID getOldDefaultUUID()

Get the UUID of the old column default.

Overrides:

getOldDefaultUUID in class ColumnDefinitionNode

Returns:

The UUID of the old column default.

getColumnPosition

public int getColumnPosition()

Get the column position for the column.

Returns:

The column position for the column.

checkUserType

public void checkUserType(TableDescriptor td)
                   throws StandardException

Check the validity of a user type. Checks that 1. the column type is either varchar, .... 2. is the same type after the alter. 3. length is greater than the old length.

Overrides:

checkUserType in class ColumnDefinitionNode

Throws:

StandardException - Thrown on error

checkExistingConstraints

public void checkExistingConstraints(TableDescriptor td)
                              throws StandardException

Check if the the column can be modified, and throw error if not. If the type of a column is being changed (for instance if the length of the column is being increased) then make sure that this does not violate any key constraints; the column being altered is 1. part of foreign key constraint ==> ERROR. This references a Primary Key constraint and the type & lengths of the pkey/fkey must match exactly. 2. part of a unique/primary key constraint ==> OK if no fkey references this constraint. ==> ERROR if any fkey in the system references this constraint.

Parameters:

td - The Table Descriptor on which the ALTER is being done.

Throws:

StandardException - Thrown on Error.

useExistingCollation

public void useExistingCollation(TableDescriptor td)
                          throws StandardException

If the column being modified is of character string type, then it should get its collation from the corresponding column in the TableDescriptor. This will ensure that at alter table time, the existing character string type columns do not loose their collation type. If the alter table is doing a drop column, then we do not need to worry about collation info.

Parameters:

td - Table Descriptor that holds the column which is being altered

Throws:

StandardException

getAction

int getAction()

Get the action associated with this node.

Overrides:

getAction in class ColumnDefinitionNode

Returns:

The action associated with this node.

bindAndValidateDefault

void bindAndValidateDefault(DataDictionary dd,
                          TableDescriptor td)
                      throws StandardException

Check the validity of the default, if any, for this node.

Overrides:

bindAndValidateDefault in class ColumnDefinitionNode

Parameters:

dd - The DataDictionary.

td - The TableDescriptor.

Throws:

StandardException - Thrown on error

getLocalColumnDescriptor

private ColumnDescriptor getLocalColumnDescriptor(java.lang.String name,
                                        TableDescriptor td)
                                           throws StandardException

Throws:

StandardException

validateAutoincrement

public void validateAutoincrement(DataDictionary dd,
                         TableDescriptor td,
                         int tableType)
                           throws StandardException

check the validity of autoincrement values in the case that we are modifying an existing column (includes checking if autoincrement is set when making a column nullable)

Overrides:

validateAutoincrement in class ColumnDefinitionNode

Parameters:

dd - DataDictionary.

td - table descriptor.

tableType - base table or declared global temporary table.

Throws:

StandardException - if autoincrement default is incorrect; i.e if increment is 0 or if initial or increment values are out of range for the datatype.