/*
* Copyright 2008 biaoping.yin
*
* 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.
*/
package com.frameworkset.orm.engine.model;
/*
* Copyright 2001,2004 The Apache Software Foundation.
*
* 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.
*/
import java.io.Serializable;
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 <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
* @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
* @version $Id: Unique.java,v 1.2 2004/02/22 06:27:19 jmcnally Exp $
*/
public class Unique extends Index implements Serializable
{
/**
* Returns <code>true</code>.
*
* @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(" <unique name=\"")
.append(getName())
.append("\">\n");
List columns = getColumns();
for (int i = 0; i < columns.size(); i++)
{
result.append(" <unique-column name=\"")
.append(columns.get(i))
.append("\"/>\n");
}
result.append(" </unique>\n");
return result.toString();
}
}