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Java Persistence API (JPA) Extensions Reference for EclipseLink, Release 2.4
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@CascadeOnDelete

Use the @CascadeOnDelete annotation to specify that a delete operation performed on a database object is cascaded on secondary or related tables.

ON DELETE CASCADE is a database foreign key constraint option that automatically removes the dependent rows.


Annotation Elements

There are no elements for this annotation.


Usage

You can place @CascadeOnDelete on any relationship in which the target is defined as foreign key to the source Entity.

Add the annotation on the source relationship: @OneToOne, @OneToMany, @ManyToMany, and @ElementCollection You can also add @CascadeOnDelete to an Entity with a @SecondaryTable or JOINED inheritance. Table 2-8 describes the affect of placing @CascadeDelete on these different elements

Table 2-8 Using @Cascade on Different Elements

Element Effect of @CascadeOnDelete

Entity

Defines that secondary or joined inheritance tables should cascade the delete on the database

OneToOne mapping

The deletion of the related object is cascaded on the database.

This is only allowed for mappedBy/target-foreign key OneToOne mappings (because of constraint direction).

OneToMany mapping

For a OneToMany using a mappedBy or JoinColumn, the deletion of the related objects is cascaded on the database.

For a OneToMany using a JoinTable, the deletion of the join table is cascaded on the database (target objects cannot be cascaded even if private because of constraint direction).

ManyToMany mapping

The deletion of the join table is cascaded on the database (target objects cannot be cascaded even if private because of constraint direction).

ElementCollection mapping

The deletion of the collection table is cascaded on the database.


@CascadeOnDelete has the following behavior:


Examples

Example 2-18 shows the cascading deletion of the Employee secondary table and all of its owned relationships.

Example 2-18 Using @CascadeOnDelete Annotation

@Entity
@SecondaryTable(name="EMP_SALARY")
@CascadeOnDelete
public class Employee{
    @Id
    private long id;
    private String firstName;
    private String lastName;
    @Column(table="EMP_SALARY")
    private String salary;
    @OneToOne(mappedBy="owner", orphanRemoval=true, cascade={CascadeType.ALL})
    @CascadeOnDelete
    private Address address;
    @OneToMany(mappedBy="owner", orphanRemoval=true, cascade={CascadeType.ALL})
    @CascadeOnDelete
    private List<Phone> phones;
    @ManyToMany
    @JoinTable(name="EMP_PROJ")
    @CascadeOnDelete
    private List<Project> projects;
    ...
}

In the eclipselink-orm.xml descriptor file, specify cascade on delete as shown in Example 2-19

Example 2-19 Using <cascade-on-delete> XML

...
<cascade-on-delete>true</cascade-on-delete>
...


See Also

For more information, see:

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