org.apache.torque.engine.database.model.Unique Maven / Gradle / Ivy
package org.apache.torque.engine.database.model;
/*
* 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.
*/
import java.util.List;
/**
* Information about unique columns of a table. This class assumes
* that in the underlying RDBMS, unique constraints and unique indices
* are roughly equivalent. For example, adding a unique constraint to
* a column also creates an index on that column (this is known to be
* true for MySQL and Oracle).
*
* @author Jason van Zyl
* @author Daniel Rall
* @version $Id: Unique.java,v 1.1 2007-10-21 07:57:27 abyrne Exp $
*/
public class Unique extends Index
{
/**
* Returns true.
*
* @return true
*/
public final boolean isUnique()
{
return true;
}
/**
* String representation of the index. This is an xml representation.
*
* @return string representation in xml
*/
public String toString()
{
StringBuffer result = new StringBuffer();
result.append(" \n");
List columns = getColumns();
for (int i = 0; i < columns.size(); i++)
{
result.append(" \n");
return result.toString();
}
}