Java tutorial
/******************************************************************************* * Copyright (c) 2008 - 2015 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: * Petros Splinakis - Java Persistence 2.2 * Linda DeMichiel - Java Persistence 2.1 * Linda DeMichiel - Java Persistence 2.0 * ******************************************************************************/ package javax.persistence; import java.lang.annotation.Repeatable; import java.lang.annotation.Target; import java.lang.annotation.Retention; import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.RetentionPolicy.RUNTIME; import static javax.persistence.ConstraintMode.PROVIDER_DEFAULT; /** * Specifies a secondary table for the annotated entity * class. Specifying one or more secondary tables indicates that the * data for the entity class is stored across multiple tables. * * <p> If no <code>SecondaryTable</code> annotation is specified, * it is assumed that all persistent fields or properties of the * entity are mapped to the primary table. If no primary key join * columns are specified, the join columns are assumed to reference * the primary key columns of the primary table, and have the same * names and types as the referenced primary key columns of the * primary table. * * <pre> * Example 1: Single secondary table with a single primary key column. * * @Entity * @Table(name="CUSTOMER") * @SecondaryTable(name="CUST_DETAIL", * pkJoinColumns=@PrimaryKeyJoinColumn(name="CUST_ID")) * public class Customer { ... } * * * Example 2: Single secondary table with multiple primary key columns. * * @Entity * @Table(name="CUSTOMER") * @SecondaryTable(name="CUST_DETAIL", * pkJoinColumns={ * @PrimaryKeyJoinColumn(name="CUST_ID"), * @PrimaryKeyJoinColumn(name="CUST_TYPE")}) * public class Customer { ... } * </pre> * * @since Java Persistence 1.0 */ @Repeatable(SecondaryTables.class) @Target(TYPE) @Retention(RUNTIME) public @interface SecondaryTable { /** (Required) The name of the table. */ String name(); /** (Optional) The catalog of the table. * <p> Defaults to the default catalog. */ String catalog() default ""; /** (Optional) The schema of the table. * <p> Defaults to the default schema for user. */ String schema() default ""; /** * (Optional) The columns that are used to join with * the primary table. * <p> Defaults to the column(s) of the same name(s) * as the primary key column(s) in the primary table. */ PrimaryKeyJoinColumn[] pkJoinColumns() default {}; /** * (Optional) Used to specify or control the generation of a * foreign key constraint for the columns corresponding to the * <code>pkJoinColumns</code> element when table generation is * in effect. If both this element and the * <code>foreignKey</code> element of any of the * <code>pkJoinColumns</code> elements are specified, the * behavior is undefined. If no foreign key annotation element * is specified in either location, the persistence provider's * default foreign key strategy will apply. * * @since Java Persistence 2.1 */ ForeignKey foreignKey() default @ForeignKey(PROVIDER_DEFAULT); /** * (Optional) Unique constraints that are to be placed on the * table. These are typically only used if table generation * is in effect. These constraints apply in addition to any * constraints specified by the <code>Column</code> and <code>JoinColumn</code> * annotations and constraints entailed by primary key mappings. * <p> Defaults to no additional constraints. */ UniqueConstraint[] uniqueConstraints() default {}; /** * (Optional) Indexes for the table. These are only used if * table generation is in effect. * * @since Java Persistence 2.1 */ Index[] indexes() default {}; }