All Downloads are FREE. Search and download functionalities are using the official Maven repository.

jakarta.persistence.JoinColumn Maven / Gradle / Ivy

There is a newer version: 3.2.0
Show newest version
/*
 * Copyright (c) 2008, 2023 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Petros Splinakis - 2.2
//     Linda DeMichiel - 2.1
//     Linda DeMichiel - 2.0

package jakarta.persistence;

import java.lang.annotation.Repeatable;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static jakarta.persistence.ConstraintMode.PROVIDER_DEFAULT;

/**
 * Specifies a column for joining an entity association or element
 * collection. If the {@code JoinColumn} annotation itself is defaulted,
 * a single join column is assumed and the default values apply.
 *
 * 

Example: * {@snippet : * @ManyToOne * @JoinColumn(name = "ADDR_ID") * public Address getAddress() { return address; } * } * *

Example: unidirectional one-to-many association using a foreign key mapping * {@snippet : * // In Customer class * @OneToMany * @JoinColumn(name = "CUST_ID") // join column is in the table for Order * public Set getOrders() { return orders; } * } * * @see ManyToOne * @see OneToMany * @see OneToOne * @see JoinTable * @see CollectionTable * @see ForeignKey * * @since 1.0 */ @Repeatable(JoinColumns.class) @Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface JoinColumn { /** * (Optional) The name of the foreign key column. * *

The table in which this column is found depends on the context. *

    *
  • If the join is for a {@link OneToOne} or {@link ManyToOne} * mapping using a foreign key mapping strategy, the foreign * key column is in the table of the source entity or embeddable. *
  • If the join is for a unidirectional {@link OneToMany} mapping * using a foreign key mapping strategy, the foreign key is in * the table of the target entity. *
  • If the join is for a {@link ManyToMany} mapping or for a * {@link OneToOne} or bidirectional {@code ManyToOne}/{@code OneToMany} * mapping using a join table, the foreign key is in a join table. *
  • If the join is for an {@link ElementCollection}, the foreign * key is in a collection table. *
* *

Default (only applies if a single join column is used): * The concatenation of the following: the name of the referencing * relationship property or field of the referencing entity or * embeddable class; "{@code _}"; the name of the referenced primary * key column. If there is no such referencing relationship property * or field in the entity, or if the join is for an element collection, * the join column name is formed as the concatenation of the following: * the name of the entity; "{@code _}"; the name of the referenced primary * key column. */ String name() default ""; /** * (Optional) The name of the column referenced by this foreign key * column. *

    *
  • When used with entity relationship mappings other than the * cases described here, the referenced column is in the table * of the target entity. *
  • When used with a unidirectional {@link OneToMany} foreign key * mapping, the referenced column is in the table of the source * entity. *
  • When used inside a {@link JoinTable} annotation, the referenced * key column is in the entity table of the owning entity, or * inverse entity if the join is part of the inverse join definition. *
  • When used in a {@link CollectionTable} mapping, the referenced * column is in the table of the entity containing the collection. *
* *

Default (only applies if single join column is being used): * The same name as the primary key column of the referenced table. */ String referencedColumnName() default ""; /** * (Optional) Whether the property is a unique key. This is a * shortcut for the {@link UniqueConstraint} annotation at the * table level and is useful for when the unique key constraint * is only a single field. It is not necessary to explicitly * specify this for a join column that corresponds to a primary * key that is part of a foreign key. */ boolean unique() default false; /** * (Optional) Whether the foreign key column is nullable. */ boolean nullable() default true; /** * (Optional) Whether the column is included in SQL INSERT * statements generated by the persistence provider. */ boolean insertable() default true; /** * (Optional) Whether the column is included in SQL UPDATE * statements generated by the persistence provider. */ boolean updatable() default true; /** * (Optional) The SQL fragment that is used when generating * the DDL for the column. *

Defaults to the generated SQL for the column. */ String columnDefinition() default ""; /** * (Optional) A SQL fragment appended to the generated DDL * which declares this column. May not be used in * conjunction with {@link #columnDefinition()}. * * @since 3.2 */ String options() default ""; /** * (Optional) The name of the table that contains the column. * If a table is not specified, the column is assumed to be * in the primary table of the applicable entity. * *

Default: *

    *
  • If the join is for a {@link OneToOne} or {@link ManyToOne} * mapping using a foreign key mapping strategy, the name of * the table of the source entity or embeddable. *
  • If the join is for a unidirectional OneToMany mapping using * a foreign key mapping strategy, the name of the table of the * target entity. *
  • If the join is for a {@link ManyToMany} mapping or for a * {@link OneToOne} or bidirectional {@code ManyToOne}/{@code OneToMany} * mapping using a join table, the name of the join table. *
  • If the join is for an element collection, the name of the * collection table. *
*/ String table() default ""; /** * (Optional) Used to specify or control the generation of a * foreign key constraint when table generation is in effect. * If this element is not specified, a default foreign key * strategy is selected by the persistence provider. * * @since 2.1 */ ForeignKey foreignKey() default @ForeignKey(PROVIDER_DEFAULT); /** * (Optional) Check constraints to be applied to the column. * These are only used if table generation is in effect. * * @since 3.2 */ CheckConstraint[] check() default {}; /** * (Optional) A comment to be applied to the column. * This is only used if table generation is in effect. * * @since 3.2 */ String comment() default ""; }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy