src/javax/persistence/SecondaryTable.java

/*******************************************************************************
 * Copyright (c) 1998, 2009 Oracle. 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:
 *     dclarke - Java Persistence 2.0 - Proposed Final Draft (March 13, 2009)
 *     		     Specification available from http://jcp.org/en/jsr/detail?id=317
 *
 * Java(TM) Persistence API, Version 2.0 - EARLY ACCESS
 * This is an implementation of an early-draft specification developed under the 
 * Java Community Process (JCP).  The code is untested and presumed not to be a  
 * compatible implementation of JSR 317: Java(TM) Persistence API, Version 2.0.   
 * We encourage you to migrate to an implementation of the Java(TM) Persistence 
 * API, Version 2.0 Specification that has been tested and verified to be compatible 
 * as soon as such an implementation is available, and we encourage you to retain 
 * this notice in any implementation of Java(TM) Persistence API, Version 2.0 
 * Specification that you distribute.
 ******************************************************************************/
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 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.
 *
 *    &#064;Entity
 *    &#064;Table(name="CUSTOMER")
 *    &#064;SecondaryTable(name="CUST_DETAIL", 
 *        pkJoinColumns=&#064;PrimaryKeyJoinColumn(name="CUST_ID"))
 *    public class Customer { ... } 
 *
 *    Example 2: Single secondary table with multiple primary key columns.
 *
 *    &#064;Entity
 *    &#064;Table(name="CUSTOMER")
 *    &#064;SecondaryTable(name="CUST_DETAIL",
 *        pkJoinColumns={
 *            &#064;PrimaryKeyJoinColumn(name="CUST_ID"),
 *            &#064;PrimaryKeyJoinColumn(name="CUST_TYPE")})
 *    public class Customer { ... }
 * </pre>
 *
 * @since Java Persistence 1.0
 */
@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) 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 {@link Column} and {@link JoinColumn} 
     * annotations and constraints entailed by primary key mappings.
     * <p> Defaults to no additional constraints.
     */
    UniqueConstraint[] uniqueConstraints() default {};
}