/*
Derby - Class org.apache.derby.iapi.sql.dictionary.ForeignKeyConstraintDescriptor
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to you under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package org.apache.derby.iapi.sql.dictionary;
import org.apache.derby.catalog.UUID;
import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.sql.StatementType;
import org.apache.derby.shared.common.sanity.SanityManager;
/**
* A foreign key.
*
*/
public class ForeignKeyConstraintDescriptor extends KeyConstraintDescriptor
{
/**
interface to this descriptor
- public ReferencedKeyConstraintDescriptor getReferencedConstraint()
throws StandardException;
- public UUID getReferencedConstraintId()
throws StandardException;
- public boolean isSelfReferencingFK()
throws StandardException;
*/
// Implementation
ReferencedKeyConstraintDescriptor referencedConstraintDescriptor;
UUID referencedConstraintId;
int raDeleteRule;
int raUpdateRule;
/**
* Constructor for a ForeignKeyConstraintDescriptor
*
* @param dataDictionary The data dictionary that this descriptor lives in
* @param table The descriptor of the table the constraint is on
* @param constraintName The name of the constraint.
* @param deferrable If the constraint can be deferred.
* @param initiallyDeferred If the constraint starts life deferred.
* @param fkColumns columns in the foreign key
* @param constraintId UUID of constraint
* @param indexId The UUID for the backing index
* @param schemaDesc The SchemaDescriptor for the constraint
* @param referencedConstraintDescriptor is referenced constraint descriptor
* @param enforced is the constraint enforced?
* @param raDeleteRule The {@code ON DELETE} action rule
* @param raUpdateRule The {@code ON UPDATE} action rule
*/
protected ForeignKeyConstraintDescriptor(
DataDictionary dataDictionary,
TableDescriptor table,
String constraintName,
boolean deferrable,
boolean initiallyDeferred,
int[] fkColumns,
UUID constraintId,
UUID indexId,
SchemaDescriptor schemaDesc,
ReferencedKeyConstraintDescriptor referencedConstraintDescriptor,
boolean enforced,
int raDeleteRule,
int raUpdateRule
)
{
super(dataDictionary, table, constraintName, deferrable,
initiallyDeferred, fkColumns,
constraintId, indexId, schemaDesc, enforced);
this.referencedConstraintDescriptor = referencedConstraintDescriptor;
this.raDeleteRule = raDeleteRule;
this.raUpdateRule = raUpdateRule;
}
/**
* Constructor for a ForeignKeyConstraintDescriptor
*
* @param dataDictionary The data dictionary that this descriptor lives in
* @param table The descriptor of the table the constraint is on
* @param constraintName The name of the constraint.
* @param deferrable If the constraint can be deferred.
* @param initiallyDeferred If the constraint starts life deferred.
* @param fkColumns columns in the foreign key
* @param constraintId UUID of constraint
* @param indexId The UUID for the backing index
* @param schemaDesc The SchemaDescriptor for the constraint
* @param referencedConstraintId is referenced constraint id
* @param enforced {@code true} if this constraint is enforced
* @param raDeleteRule The {@code ON DELETE} action rule
* @param raUpdateRule The {@code ON UPDATE} action rule
*/
ForeignKeyConstraintDescriptor(
DataDictionary dataDictionary,
TableDescriptor table,
String constraintName,
boolean deferrable,
boolean initiallyDeferred,
int[] fkColumns,
UUID constraintId,
UUID indexId,
SchemaDescriptor schemaDesc,
UUID referencedConstraintId,
boolean enforced,
int raDeleteRule,
int raUpdateRule
)
{
super(dataDictionary, table, constraintName, deferrable,
initiallyDeferred, fkColumns,
constraintId, indexId, schemaDesc, enforced);
this.referencedConstraintId = referencedConstraintId;
this.raDeleteRule = raDeleteRule;
this.raUpdateRule = raUpdateRule;
}
/**
* Get the constraint that this FK references. Will
* return either a primary key or a unique key constraint.
*
* @return the constraint
*
* @exception StandardException on error
*/
public ReferencedKeyConstraintDescriptor getReferencedConstraint()
throws StandardException
{
if (referencedConstraintDescriptor != null)
{
return referencedConstraintDescriptor;
}
if (referencedConstraintId == null)
{
getReferencedConstraintId();
}
TableDescriptor refTd = getDataDictionary().getConstraintTableDescriptor(referencedConstraintId);
if (SanityManager.DEBUG)
{
if (refTd == null)
{
SanityManager.THROWASSERT("not able to find "+referencedConstraintId+
" in SYS.SYSCONSTRAINTS");
}
}
ConstraintDescriptorList cdl = getDataDictionary().getConstraintDescriptors(refTd);
referencedConstraintDescriptor = (ReferencedKeyConstraintDescriptor)
cdl.getConstraintDescriptorById(referencedConstraintId);
if (SanityManager.DEBUG)
{
if (referencedConstraintDescriptor == null)
{
SanityManager.THROWASSERT("not able to find "
+referencedConstraintDescriptor+ " off of table descriptor "
+refTd.getName());
}
}
return referencedConstraintDescriptor;
}
/**
* Get the constraint id for the constraint that this FK references.
* Will return either a primary key or a unique key constriant.
*
* @return the constraint id
*
* @exception StandardException on error
*/
public UUID getReferencedConstraintId() throws StandardException
{
if (referencedConstraintDescriptor != null)
{
return referencedConstraintDescriptor.getUUID();
}
SubKeyConstraintDescriptor subKey;
subKey = getDataDictionary().getSubKeyConstraint(constraintId,
DataDictionary.FOREIGNKEY_CONSTRAINT);
if (SanityManager.DEBUG)
{
if (subKey == null)
{
SanityManager.THROWASSERT("not able to find "+constraintName+
" in SYS.SYSFOREIGNKEYS");
}
}
referencedConstraintId = subKey.getKeyConstraintId();
return referencedConstraintId;
}
/**
* Gets an identifier telling what type of descriptor it is
* (UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK).
*
* @return An identifier telling what type of descriptor it is
* (UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK).
*/
@Override
public int getConstraintType()
{
return DataDictionary.FOREIGNKEY_CONSTRAINT;
}
/**
* Does this constraint need to fire on this type of
* DML? True if insert or update and columns intersect
*
* @param stmtType the type of DML
* (StatementType.INSERT|StatementType.UPDATE|StatementType.DELETE)
* @param modifiedCols the columns modified, or null for all
*
* @return true/false
*/
@Override
public boolean needsToFire(int stmtType, int[] modifiedCols)
{
/*
** If we are disabled, we never fire
*/
if (!enforced())
{
return false;
}
if (stmtType == StatementType.DELETE)
{
return false;
}
if (stmtType == StatementType.INSERT)
{
return true;
}
// if update, only relevant if columns intersect
return doColumnsIntersect(modifiedCols, getReferencedColumns());
}
/**
* Am I a self-referencing FK? True if my referenced
* constraint is on the same table as me.
*
* @return true/false
*
* @exception StandardException on error
*/
public boolean isSelfReferencingFK()
throws StandardException
{
ReferencedKeyConstraintDescriptor refcd = getReferencedConstraint();
return (refcd.getTableId().equals(getTableId()));
}
/**
* Gets a referential action rule on a DELETE
* @return referential rule defined by the user during foreign key creattion
* for a delete (like CASCDE , RESTRICT ..etc)
*/
public int getRaDeleteRule()
{
return raDeleteRule;
}
/**
* Gets a referential action rule on a UPDATE
* @return referential rule defined by the user during foreign key creattion
* for an UPDATE (like CASCDE , RESTRICT ..etc)
*/
public int getRaUpdateRule()
{
return raUpdateRule;
}
}
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