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 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.dba.postgres;

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

/**
 * Default PK generator for PostgreSQL that uses sequences for PK generation.
 */
public class PostgresPkGenerator extends OraclePkGenerator {

	protected PostgresPkGenerator(JdbcAdapter adapter) {
		super(adapter);
	}

	@Override
	protected String createSequenceString(DbEntity ent) {
		// note that PostgreSQL 7.4 and newer supports INCREMENT BY and START WITH
		// however 7.3 doesn't like BY and WITH, so using older more neutral
		// syntax that works with all tested versions.
		return "CREATE SEQUENCE " + sequenceName(ent) + " INCREMENT " + pkCacheSize(ent) + " START " + pkStartValue;
	}

	@Override
	protected String selectNextValQuery(String sequenceName) {
		return "SELECT nextval('" + sequenceName + "')";
	}

	@Override
	protected String selectAllSequencesQuery() {
		return "SELECT relname FROM pg_class WHERE relkind='S'";
	}
}