org.hibernate.mapping.ForeignKey Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*
*/
package org.hibernate.mapping;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.hibernate.MappingException;
import org.hibernate.dialect.Dialect;
/**
* A foreign key constraint
* @author Gavin King
*/
public class ForeignKey extends Constraint {
private Table referencedTable;
private String referencedEntityName;
private boolean cascadeDeleteEnabled;
private List referencedColumns = new ArrayList();
public String sqlConstraintString(Dialect dialect, String constraintName, String defaultCatalog, String defaultSchema) {
String[] cols = new String[ getColumnSpan() ];
String[] refcols = new String[ getColumnSpan() ];
int i=0;
Iterator refiter = null;
if(isReferenceToPrimaryKey() ) {
refiter = referencedTable.getPrimaryKey().getColumnIterator();
}
else {
refiter = referencedColumns.iterator();
}
Iterator iter = getColumnIterator();
while ( iter.hasNext() ) {
cols[i] = ( (Column) iter.next() ).getQuotedName(dialect);
refcols[i] = ( (Column) refiter.next() ).getQuotedName(dialect);
i++;
}
String result = dialect.getAddForeignKeyConstraintString(
constraintName, cols, referencedTable.getQualifiedName(dialect, defaultCatalog, defaultSchema), refcols, isReferenceToPrimaryKey()
);
return cascadeDeleteEnabled && dialect.supportsCascadeDelete() ?
result + " on delete cascade" :
result;
}
public Table getReferencedTable() {
return referencedTable;
}
private void appendColumns(StringBuffer buf, Iterator columns) {
while( columns.hasNext() ) {
Column column = (Column) columns.next();
buf.append( column.getName() );
if ( columns.hasNext() ) buf.append(",");
}
}
public void setReferencedTable(Table referencedTable) throws MappingException {
//if( isReferenceToPrimaryKey() ) alignColumns(referencedTable); // TODO: possibly remove to allow more piecemal building of a foreignkey.
this.referencedTable = referencedTable;
}
/**
* Validates that columnspan of the foreignkey and the primarykey is the same.
*
* Furthermore it aligns the length of the underlying tables columns.
* @param referencedTable
*/
public void alignColumns() {
if ( isReferenceToPrimaryKey() ) alignColumns(referencedTable);
}
private void alignColumns(Table referencedTable) {
if ( referencedTable.getPrimaryKey().getColumnSpan()!=getColumnSpan() ) {
StringBuffer sb = new StringBuffer();
sb.append("Foreign key (")
.append( getName() + ":")
.append( getTable().getName() )
.append(" [");
appendColumns( sb, getColumnIterator() );
sb.append("])")
.append(") must have same number of columns as the referenced primary key (")
.append( referencedTable.getName() )
.append(" [");
appendColumns( sb, referencedTable.getPrimaryKey().getColumnIterator() );
sb.append("])");
throw new MappingException( sb.toString() );
}
Iterator fkCols = getColumnIterator();
Iterator pkCols = referencedTable.getPrimaryKey().getColumnIterator();
while ( pkCols.hasNext() ) {
( (Column) fkCols.next() ).setLength( ( (Column) pkCols.next() ).getLength() );
}
}
public String getReferencedEntityName() {
return referencedEntityName;
}
public void setReferencedEntityName(String referencedEntityName) {
this.referencedEntityName = referencedEntityName;
}
public String sqlDropString(Dialect dialect, String defaultCatalog, String defaultSchema) {
return "alter table " +
getTable().getQualifiedName(dialect, defaultCatalog, defaultSchema) +
dialect.getDropForeignKeyString() +
getName();
}
public boolean isCascadeDeleteEnabled() {
return cascadeDeleteEnabled;
}
public void setCascadeDeleteEnabled(boolean cascadeDeleteEnabled) {
this.cascadeDeleteEnabled = cascadeDeleteEnabled;
}
public boolean isPhysicalConstraint() {
return referencedTable.isPhysicalTable() &&
getTable().isPhysicalTable() &&
!referencedTable.hasDenormalizedTables();
}
/** Returns the referenced columns if the foreignkey does not refer to the primary key */
public List getReferencedColumns() {
return referencedColumns;
}
/** Does this foreignkey reference the primary key of the reference table */
public boolean isReferenceToPrimaryKey() {
return referencedColumns.isEmpty();
}
public void addReferencedColumns(Iterator referencedColumnsIterator) {
while ( referencedColumnsIterator.hasNext() ) {
Selectable col = (Selectable) referencedColumnsIterator.next();
if ( !col.isFormula() ) addReferencedColumn( (Column) col );
}
}
private void addReferencedColumn(Column column) {
if ( !referencedColumns.contains(column) ) referencedColumns.add(column);
}
public String toString() {
if(!isReferenceToPrimaryKey() ) {
StringBuffer result = new StringBuffer(getClass().getName() + '(' + getTable().getName() + getColumns() );
result.append( " ref-columns:" + '(' + getReferencedColumns() );
result.append( ") as " + getName() );
return result.toString();
}
else {
return super.toString();
}
}
}