/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
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 */
package javax.persistence;

import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * This annotation is used to specify 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 {

    /** (Required) An array of the column names that make up the constraint. */
    String[] columnNames();
}