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Difference between revisions of "EclipseLink/UserGuide/JPA/Advanced JPA Development/Schema Generation/CascadeOnDelete"
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ON DELETE CASCADE is a database foreign key constraint option that automatically removes the dependent rows. | ON DELETE CASCADE is a database foreign key constraint option that automatically removes the dependent rows. | ||
− | Use the <tt>@CascadeOnDelete</tt> annotation or the <tt> | + | Use the <tt>@CascadeOnDelete</tt> annotation or the <tt>cascade-on-delete</tt> XML element to specify that a delete operation performed on a database object is cascaded on secondary or related tables. |
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| The deletion of the join table is cascaded on the database. (Target objects cannot be cascaded even if private because of constraint direction). | | The deletion of the join table is cascaded on the database. (Target objects cannot be cascaded even if private because of constraint direction). | ||
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− | | | + | | ElementCollection |
− | | The deletion of the | + | | The deletion of the collection table is cascaded on the database. |
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</source> | </source> | ||
− | + | Usage of @CascadeOnDelete has the following behavior: | |
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− | * | + | * DDL generation : if DDL generation is used, the generated constraint will include the cascade deletion option. |
+ | * Entity : Remove will not execute SQL for deletion from secondary or joined inheritance tables (as constraint will handle deletion). | ||
+ | * OneToOne : If the mapping uses cascading or orphanRemoval, SQL will not be executed to delete target object. | ||
+ | * OneToMany : If the mapping uses cascading or orphanRemoval, SQL will not be executed to delete target objects. | ||
+ | * ManyToMany : SQL will not be executed to delete from the join table. | ||
+ | * ElementCollection : SQL will not be executed to delete from the collection table. | ||
= Configuration File = | = Configuration File = |
Revision as of 14:36, 1 February 2011
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Key API CascadeOnDelete
@CascadeOnDelete
>>>>>> THIS PAGE IS IN PROGRESS. PLEASE SEE DISCUSSION PAGE. <<<<<<
ON DELETE CASCADE is a database foreign key constraint option that automatically removes the dependent rows.
Use the @CascadeOnDelete annotation or the cascade-on-delete XML element to specify that a delete operation performed on a database object is cascaded on secondary or related tables.
Performing a CascadeOnDelete on this object... | Does this... |
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-foriegn key OneToOne mappings (because of constraint direction). |
OneToMany mapping | The deletion of the related objects is cascaded on the database. |
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 | The deletion of the collection table is cascaded on the database. |
@Target(value={METHOD,FIELD,TYPE}) @Retention(value=RUNTIME) public @interface CascadeOnDelete
Usage of @CascadeOnDelete has the following behavior:
- DDL generation : if DDL generation is used, the generated constraint will include the cascade deletion option.
- Entity : Remove will not execute SQL for deletion from secondary or joined inheritance tables (as constraint will handle deletion).
- OneToOne : If the mapping uses cascading or orphanRemoval, SQL will not be executed to delete target object.
- OneToMany : If the mapping uses cascading or orphanRemoval, SQL will not be executed to delete target objects.
- ManyToMany : SQL will not be executed to delete from the join table.
- ElementCollection : SQL will not be executed to delete from the collection table.
Configuration File
In the orm.xml descriptor file, specify cascade on delete as follows:
<source lang="xml"> <entity cascadeOnDelete="true"> <one-to-one cascadeOnDelete="true"> <one-to-many cascadeOnDelete="true"> <many-to-many cascadeOnDelete="true"> </source>