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Plugin for DataNucleus providing persistence to RDBMS datastores.
/**********************************************************************
Copyright (c) 2003 Mike Martin (TJDO) and others. All rights reserved.
Licensed 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.
Contributors:
2003 Andy Jefferson - equality operator
2004 Andy Jefferson - deleteAction, updateAction, MetaData interface
2008 Andy Jefferson - rewritten to use enums for actions
...
**********************************************************************/
package org.datanucleus.store.rdbms.key;
import java.util.ArrayList;
import java.util.List;
import org.datanucleus.exceptions.NucleusException;
import org.datanucleus.metadata.ForeignKeyAction;
import org.datanucleus.metadata.ForeignKeyMetaData;
import org.datanucleus.store.rdbms.adapter.DatastoreAdapter;
import org.datanucleus.store.rdbms.mapping.java.JavaTypeMapping;
import org.datanucleus.store.rdbms.table.Column;
import org.datanucleus.store.rdbms.table.DatastoreClass;
/**
* Representation of a foreign key to another table.
*/
public class ForeignKey extends Key
{
/** Enum representing an action on the FK. */
public static enum FKAction
{
CASCADE("CASCADE"),
RESTRICT("RESTRICT"),
NULL("SET NULL"),
DEFAULT("SET DEFAULT");
String keyword;
private FKAction(String word)
{
this.keyword = word;
}
public String toString()
{
return keyword;
}
}
private DatastoreAdapter dba;
private boolean initiallyDeferred;
private DatastoreClass refTable;
private FKAction updateAction;
private FKAction deleteAction;
private List refColumns = new ArrayList<>();
private String foreignKeyDefinition = null;
/**
* Constructor.
* @param dba Datastore adapter
* @param initiallyDeferred Whether the constraints are deferred
*/
public ForeignKey(DatastoreAdapter dba, boolean initiallyDeferred)
{
super(null);
this.initiallyDeferred = initiallyDeferred;
this.refTable = null;
this.dba = dba;
}
/**
* Constructor.
* @param mapping The type mapping for this Foreign-key field
* @param dba Datastore adapter
* @param refTable Referred to table
* @param initiallyDeferred Whether they are deferred
*/
public ForeignKey(JavaTypeMapping mapping, DatastoreAdapter dba, DatastoreClass refTable, boolean initiallyDeferred)
{
super(mapping.getTable());
this.initiallyDeferred = initiallyDeferred;
this.refTable = refTable;
this.dba = dba;
if (refTable.getIdMapping() == null)
{
throw new NucleusException("ForeignKey ID mapping is not initilized for "+mapping+". Table referenced: " + refTable.toString()).setFatal();
}
for (int i=0; iseq
* @param seq the specified position
* @param col the datastore field
* @param refCol the foreign (refered) datastore field
*/
public void setColumn(int seq, Column col, Column refCol)
{
if (table == null)
{
table = col.getTable();
refTable = (DatastoreClass) refCol.getTable();
dba = table.getStoreManager().getDatastoreAdapter();
}
else
{
if (!table.equals(col.getTable()))
{
throw new NucleusException("Cannot add " + col + " as FK column for " + table).setFatal();
}
if (!refTable.equals(refCol.getTable()))
{
throw new NucleusException("Cannot add " + refCol + " as referenced FK column for " + refTable).setFatal();
}
}
setMinSize(columns, seq + 1);
setMinSize(refColumns, seq + 1);
columns.set(seq, col);
refColumns.set(seq, refCol);
}
public int hashCode()
{
if (foreignKeyDefinition != null)
{
return foreignKeyDefinition.hashCode();
}
return super.hashCode() ^ refColumns.hashCode();
}
public boolean equals(Object obj)
{
if (obj == this)
{
return true;
}
if (!(obj instanceof ForeignKey))
{
return false;
}
ForeignKey fk = (ForeignKey)obj;
if (refColumns != null && !refColumns.equals(fk.refColumns))
{
return false;
}
// TODO Enable this. Sadly some RDBMS (e.g HSQLDB) don't always return all info so we end up
// For example "test.jdo.orm.application" RelationshipTest where we have
// this = FOREIGN KEY (BOILER_ID) REFERENCES HEATING_BOILER (BOILER_ID) ON DELETE SET NULL
// other = FOREIGN KEY (BOILER_ID) REFERENCES HEATING_BOILER (BOILER_ID)
// These should be equal, but the latter hasn't had all info returned
/* if (!toString().equals(fk.toString()))
{
return false;
}*/
return super.equals(obj);
}
public boolean isEqual(ForeignKey fk)
{
String colList = getColumnList();
String refColList = getRefColumnList();
if (colList == null && fk.getColumnList() != null)
{
return false;
}
if (refColList == null && fk.getRefColumnList() != null)
{
return false;
}
if (colList != null && colList.equals(fk.getColumnList()) && getTable() == fk.getTable() &&
refColList != null && refColList.equals(fk.getRefColumnList()) && getRefTable().equals(fk.getRefTable()))
{
return true;
}
return false;
}
/**
* Stringify method. Generates the foreign key statement ready for use in an SQL call.
* @return String version of this object.
**/
public String toString()
{
if (foreignKeyDefinition != null)
{
// User-provided definition
return foreignKeyDefinition;
}
StringBuilder s = new StringBuilder("FOREIGN KEY ");
s.append(getColumnList(columns));
// Referenced table
if (refTable != null)
{
// Include the referenced column list because some RDBMS require it (e.g MySQL)
s.append(" REFERENCES ");
s.append(refTable.toString());
s.append(" ").append(getColumnList(refColumns));
}
// Delete action
if (deleteAction != null)
{
if ((deleteAction == FKAction.CASCADE && dba.supportsOption(DatastoreAdapter.FK_DELETE_ACTION_CASCADE)) ||
(deleteAction == FKAction.RESTRICT && dba.supportsOption(DatastoreAdapter.FK_DELETE_ACTION_RESTRICT)) ||
(deleteAction == FKAction.NULL && dba.supportsOption(DatastoreAdapter.FK_DELETE_ACTION_NULL)) ||
(deleteAction == FKAction.DEFAULT && dba.supportsOption(DatastoreAdapter.FK_DELETE_ACTION_DEFAULT)))
{
s.append(" ON DELETE ").append(deleteAction.toString());
}
}
// Update action
if (updateAction != null)
{
if ((updateAction == FKAction.CASCADE && dba.supportsOption(DatastoreAdapter.FK_UPDATE_ACTION_CASCADE)) ||
(updateAction == FKAction.RESTRICT && dba.supportsOption(DatastoreAdapter.FK_UPDATE_ACTION_RESTRICT)) ||
(updateAction == FKAction.NULL && dba.supportsOption(DatastoreAdapter.FK_UPDATE_ACTION_NULL)) ||
(updateAction == FKAction.DEFAULT && dba.supportsOption(DatastoreAdapter.FK_UPDATE_ACTION_DEFAULT)))
{
s.append(" ON UPDATE ").append(updateAction.toString());
}
}
// Deferral of constraints
if (initiallyDeferred && dba.supportsOption(DatastoreAdapter.DEFERRED_CONSTRAINTS))
{
s.append(" INITIALLY DEFERRED");
}
s.append(" ");
return s.toString();
}
}