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 *   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
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package org.apache.cayenne.dba.db2;

import org.apache.cayenne.dba.JdbcAdapter;
import org.apache.cayenne.dba.oracle.OraclePkGenerator;
import org.apache.cayenne.map.DbEntity;

/**
 * A sequence-based PK generator used by {@link DB2Adapter}.
 */
public class DB2PkGenerator extends OraclePkGenerator {

	DB2PkGenerator(JdbcAdapter adapter) {
		super(adapter);
	}

	private static final String _SEQUENCE_PREFIX = "S_";

	@Override
	protected String sequenceName(DbEntity entity) {
		return super.sequenceName(entity).toUpperCase();
	}

	@Override
	protected String getSequencePrefix() {
		return _SEQUENCE_PREFIX;
	}

	@Override
	protected String selectNextValQuery(String pkGeneratingSequenceName) {
		return "SELECT NEXTVAL FOR " + pkGeneratingSequenceName + " FROM SYSIBM.SYSDUMMY1";
	}

	@Override
	protected String selectAllSequencesQuery() {
		return "SELECT SEQNAME FROM SYSCAT.SEQUENCES WHERE SEQNAME LIKE '" + _SEQUENCE_PREFIX + "%'";
	}

	@Override
	protected String dropSequenceString(DbEntity entity) {
		return "DROP SEQUENCE " + sequenceName(entity) + " RESTRICT ";
	}

	@Override
	protected String createSequenceString(DbEntity entity) {
		return "CREATE SEQUENCE " + sequenceName(entity) + " AS BIGINT START WITH " + pkStartValue +
				" INCREMENT BY " + getPkCacheSize() + " NO MAXVALUE NO CYCLE CACHE " + getPkCacheSize();
	}
}