org.hibernate.dialect.DB2400V7R3Dialect Maven / Gradle / Ivy

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Hibernate's core ORM functionality

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or .
 */
package org.hibernate.dialect;

import org.hibernate.dialect.identity.DB2IdentityColumnSupport;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import org.hibernate.dialect.unique.DefaultUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;

/**
 * An SQL dialect for i. This class provides support for DB2 Universal Database for i V7R1 and
 * later, also known as DB2/400.
 *
 * @author Pierrick Rouxel (pierrickrouxel)
 */
public class DB2400V7R3Dialect extends DB2400Dialect {

	private final UniqueDelegate uniqueDelegate;

	public DB2400V7R3Dialect() {
		super();

		uniqueDelegate = new DefaultUniqueDelegate(this);
	}

	@Override
	public UniqueDelegate getUniqueDelegate() {
		return uniqueDelegate;
	}

	@Override
	public boolean supportsSequences() {
		return true;
	}

	@Override
	public String getQuerySequencesString() {
		return "select distinct sequence_name from qsys2.syssequences " +
				"where ( current_schema = '*LIBL' and sequence_schema in ( select schema_name from qsys2.library_list_info ) ) " +
				"or sequence_schema = current_schema";
	}

	@Override
	@SuppressWarnings("deprecation")
	public String getLimitString(String sql, int offset, int limit) {
		if ( offset == 0 ) {
			return sql + " fetch first " + limit + " rows only";
		}
		//nest the main query in an outer select
		return "select * from ( select inner2_.*, rownumber() over(order by order of inner2_) as rownumber_ from ( "
				+ sql + " fetch first " + limit + " rows only ) as inner2_ ) as inner1_ where rownumber_ > "
				+ offset + " order by rownumber_";
	}

	@Override
	public IdentityColumnSupport getIdentityColumnSupport() {
		return new DB2IdentityColumnSupport();
	}
}