javax.persistence.EntityResult Maven / Gradle / Ivy

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// $Id: EntityResult.java 17752 2009-10-15 01:19:21Z [email protected] $
// EJB3 Specification Copyright 2004-2009 Sun Microsystems, Inc.
package javax.persistence;

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

/**
 * Used to map the SELECT clause of a SQL query to an entity result.
 * 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.
 *
 *  *   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)
 *   })
 * 
 *
 * @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 "";
}