Java tutorial
/******************************************************************************* * Copyright (c) 2008 - 2014 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; /** * Used in conjunction with the {@link SqlResultSetMapping} annotation to map the SELECT * clause of a SQL query to an entity result. * * <p>If this annotation is used, the SQL statement should select * all of the columns that are mapped to the entity object. * This should include foreign key columns to related entities. * The results obtained when insufficient data is available * are undefined. * * <pre> * Example: * * Query q = em.createNativeQuery( * "SELECT o.id, o.quantity, o.item, i.id, i.name, i.description "+ * "FROM Order o, Item i " + * "WHERE (o.quantity > 25) AND (o.item = i.id)", * "OrderItemResults"); * @SqlResultSetMapping(name="OrderItemResults", * entities={ * @EntityResult(entityClass=com.acme.Order.class), * @EntityResult(entityClass=com.acme.Item.class) * }) * </pre> * * @see SqlResultSetMapping * * @since Java Persistence 1.0 */ @Target({}) @Retention(RUNTIME) public @interface EntityResult { /** The class of the result. */ Class entityClass(); /** * Maps the columns specified in the SELECT list of the * query to the properties or fields of the entity class. */ FieldResult[] fields() default {}; /** * Specifies the column name (or alias) of the column in * the SELECT list that is used to determine the type of * the entity instance. */ String discriminatorColumn() default ""; }