001/*
002 * Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
003 *
004 * This program and the accompanying materials are made available under the
005 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
006 * which accompanies this distribution.  The Eclipse Public License is available
007 * at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
008 * is available at http://www.eclipse.org/org/documents/edl-v10.php.
009 */
010package javax.persistence;
011
012import java.lang.annotation.Retention;
013import java.lang.annotation.Target;
014
015import static java.lang.annotation.RetentionPolicy.RUNTIME;
016
017/**
018 * Used to map the SELECT clause of a SQL query to an entity result. If this annotation is used, the SQL
019 * statement should select all of the columns that are mapped to the entity object. This should include
020 * foreign key columns to related entities. The results obtained when insufficient data is available are
021 * undefined.
022 * <p>
023 * <pre>
024 *   Example:
025 *
026 *   Query q = em.createNativeQuery(
027 *       "SELECT o.id, o.quantity, o.item, i.id, i.name, i.description "+
028 *           "FROM Order o, Item i " +
029 *           "WHERE (o.quantity &gt; 25) AND (o.item = i.id)",
030 *       "OrderItemResults");
031 *   &#064;SqlResultSetMapping(name="OrderItemResults",
032 *       entities={
033 *           &#064;EntityResult(entityClass=com.acme.Order.class),
034 *           &#064;EntityResult(entityClass=com.acme.Item.class)
035 *   })
036 * </pre>
037 *
038 * @see SqlResultSetMapping
039 * @since Java Persistence 1.0
040 */
041@Target({})
042@Retention(RUNTIME)
043public @interface EntityResult {
044
045  /**
046   * The class of the result.
047   *
048   * @return entity class
049   */
050  Class entityClass();
051
052  /**
053   * Maps the columns specified in the SELECT list of the query to the properties or fields of the entity
054   * class.
055   *
056   * @return fields
057   */
058  FieldResult[] fields() default {};
059
060  /**
061   * Specifies the column name (or alias) of the column in the SELECT list that is used to determine the
062   * type of the entity instance.
063   *
064   * @return disc col
065   */
066  String discriminatorColumn() default "";
067}