Java tutorial
/******************************************************************************* * Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * Contributors: * Linda DeMichiel - Java Persistence 2.1 * Linda DeMichiel - Java Persistence 2.0 * ******************************************************************************/ package javax.persistence; import java.lang.annotation.Target; import java.lang.annotation.Retention; import static java.lang.annotation.RetentionPolicy.RUNTIME; /** * Specifies that a unique constraint is to be included in * the generated DDL for a primary or secondary table. * * <pre> * Example: * @Entity * @Table( * name="EMPLOYEE", * uniqueConstraints= * @UniqueConstraint(columnNames={"EMP_ID", "EMP_NAME"}) * ) * public class Employee { ... } * </pre> * * @since Java Persistence 1.0 */ @Target({}) @Retention(RUNTIME) public @interface UniqueConstraint { /** (Optional) Constraint name. A provider-chosen name will be chosen * if a name is not specified. * * @since Java Persistence 2.0 */ String name() default ""; /** (Required) An array of the column names that make up the constraint. */ String[] columnNames(); }