| /*******************************************************************************
|
| * 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;
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| import static java.lang.annotation.ElementType.FIELD;
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| import static java.lang.annotation.ElementType.METHOD;
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| import static java.lang.annotation.RetentionPolicy.RUNTIME;
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| import static javax.persistence.ConstraintMode.PROVIDER_DEFAULT;
|
|
|
| /**
|
| * Specifies a mapping to an entity that is a map key. The map key
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| * join column is in the collection table, join table, or table of the
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| * target entity that is used to represent the map. If no
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| * <code>MapKeyJoinColumn</code> annotation is specified, a single
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| * join column is assumed and the default values apply.
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| *
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| * <pre>
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| *
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| * Example 1:
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| *
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| * @Entity
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| * public class Company {
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| * @Id int id;
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| * ...
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| * @OneToMany // unidirectional
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| * @JoinTable(name="COMPANY_ORGANIZATION",
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| * joinColumns=@JoinColumn(name="COMPANY"),
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| * inverseJoinColumns=@JoinColumn(name="VICEPRESIDENT"))
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| * @MapKeyJoinColumn(name="DIVISION")
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| * Map<Division, VicePresident> organization;
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| * }
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| *
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| * Example 2:
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| *
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| * @Entity
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| * public class VideoStore {
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| * @Id int id;
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| * String name;
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| * Address location;
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| * ...
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| * @ElementCollection
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| * @CollectionTable(name="INVENTORY",
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| * joinColumns=@JoinColumn(name="STORE"))
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| * @Column(name="COPIES_IN_STOCK")
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| * @MapKeyJoinColumn(name="MOVIE", referencedColumnName="ID")
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| * Map<Movie, Integer> videoInventory;
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| * ...
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| * }
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| *
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| * @Entity
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| * public class Movie {
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| * @Id long id;
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| * String title;
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| * ...
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| * }
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| *
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| * Example 3:
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| *
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| * @Entity
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| * public class Student {
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| * @Id int studentId;
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| * ...
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| * @ManyToMany // students and courses are also many-many
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| * @JoinTable(name="ENROLLMENTS",
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| * joinColumns=@JoinColumn(name="STUDENT"),
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| * inverseJoinColumns=@JoinColumn(name="SEMESTER"))
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| * @MapKeyJoinColumn(name="COURSE")
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| * Map<Course, Semester> enrollment;
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| * ...
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| * }
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| * </pre>
|
| *
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| * @see ForeignKey
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| *
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| * @since Java Persistence 2.0
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| */
|
| @Repeatable(MapKeyJoinColumns.class) |
| @Target( { METHOD, FIELD })
|
| @Retention(RUNTIME)
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| public @interface MapKeyJoinColumn {
|
| /**
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| * (Optional) The name of the foreign key column for the map
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| * key. The table in which it is found depends upon the
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| * context.
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| * <ul>
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| * <li> If the join is for a map key for an
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| * element collection, the foreign key column is in the
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| * collection table for the map value.
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| * <li> If the join is for a map key for a ManyToMany entity
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| * relationship or for a OneToMany entity relationship
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| * using a join table, the foreign key column is in a join table.
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| * <li> If the join is for a OneToMany entity relationship using
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| * a foreign key mapping strategy, the foreign key column for the
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| * map key is in the table of the entity that is the value of the map.
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| * </ul>
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| *
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| * <p> Default (only applies if a single join column is used.)
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| * The concatenation of the following: the name of the
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| * referencing relationship property or field of the
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| * referencing entity or embeddable class; "_"; "KEY".
|
| */
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| String name() default "";
|
|
|
| /**
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| * (Optional) The name of the column referenced by this foreign key column.
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| * The referenced column is in the table of the target entity.
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| *
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| * <p> Default (only applies if single join column is being
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| * used.) The same name as the primary key column of the
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| * referenced table
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| */
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| String referencedColumnName() default "";
|
|
|
| /**
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| * (Optional) Whether the property is a unique key. This is a
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| * shortcut for the <code>UniqueConstraint</code> annotation
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| * at the table level and is useful for when the unique key
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| * constraint is only a single field.
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| */
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| boolean unique() default false;
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|
|
| /**
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| * (Optional) Whether the foreign key column is nullable.
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| */
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| boolean nullable() default false;
|
|
|
| /**
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| * (Optional) Whether the column is included in SQL INSERT statements
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| * generated by the persistence provider.
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| */
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| boolean insertable() default true;
|
|
|
| /**
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| * (Optional) Whether the column is included in SQL UPDATE statements
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| * generated by the persistence provider.
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| */
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| boolean updatable() default true;
|
|
|
| /**
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| * (Optional) The SQL fragment that is used when generating the DDL for the
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| * column.
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| * Defaults to SQL generated by the provider for the column.
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| */
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| String columnDefinition() default "";
|
|
|
| /**
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| * (Optional) The name of the table that contains the foreign key column.
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| * <ul>
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| * <li> If the join is for a map key for an element collection, the foreign key
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| * column is in the collection table for the map value.
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| * <li> If the join is for a map key for a ManyToMany entity relationship
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| * or for a OneToMany entity relationship using a join table,
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| * the foreign key column is in a join table.
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| * <li> If the join is for a OneToMany entity relationship using a foreign
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| * key mapping strategy, the foreign key column for the map key is in the
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| * table of the entity that is the value of the map.
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| * </ul>
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| * <p> Default:
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| * <ul>
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| * <li> If the map is for an element collection, the
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| * name of the collection table for the map value.
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| * <li> If the map is for a OneToMany or ManyToMany entity relationship
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| * using a join table, the name of the join table for the map.
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| * <li> If the map is for a OneToMany entity relationship using a
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| * foreign key mapping strategy, the name of the primary table
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| * of the entity that is the value of the map.
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| * </ul>
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| */
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| String table() default "";
|
|
|
| /**
|
| * (Optional) Used to specify or control the generation of a
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| * foreign key constraint when table generation is in effect. If
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| * this element is not specified, the persistence provider's
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| * default foreign key strategy will apply.
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| *
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| * @since Java Persistence 2.1
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| */
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| ForeignKey foreignKey() default @ForeignKey(PROVIDER_DEFAULT);
|
| }
|
