Using Hibernate #SQLDelete for Soft Delete across All Entities - mysql

Question

We have a fairly complex data model and are using Hibernate and Spring Data JPA on top of MySQL. We have a base class that all domain objects extend to minimize boiler plate code. I would like to be able to add soft delete functionality across all of our domain objects using only this class. However, #SQLDelete requires the table name in the clause:
#SQLDelete(sql="UPDATE (table_name) SET deleted = '1' WHERE id = ?")
#Where(clause="deleted <> '1'")
Does anybody know of a way to generalize the SQLDelete statement and allow the extending domain objects to populate their own table names?

Answer 1

If you use hibernate and #SQLDelete, there's no easy solution to your question. But you can consider another approach to soft delete with Spring Data's expression language:
#Override
#Query("select e from #{#entityName} e where e.deleteFlag=false")
public List<T> findAll();
//recycle bin
#Query("select e from #{#entityName} e where e.deleteFlag=true")
public List<T> recycleBin();
#Query("update #{#entityName} e set e.deleteFlag=true where e.id=?1")
#Modifying
public void softDelete(String id);
//#{#entityName} will be substituted by concrete entity name automatically.
Rewrite base repository like this. All sub repository interfaces will have soft delete ability.

Answer 2

Another approach, which could be more flexible.
On Entity level create
#MappedSuperclass
public class SoftDeletableEntity {
public static final String SOFT_DELETED_CLAUSE = "IS_DELETED IS FALSE";
#Column(name = "is_deleted")
private boolean isDeleted;
...
}
Update your Entity which should be soft deletable
#Entity
#Where(clause = SoftDeletableEntity.SOFT_DELETED_CLAUSE)
#Table(name = "table_name")
public class YourEntity extends SoftDeletableEntity {...}
Create a custom Interface Repository which extends the Spring's Repository. Add default methods for soft delete. It should be as a base repo for your Repositories. e.g.
#NoRepositoryBean
public interface YourBaseRepository<T, ID> extends JpaRepository<T, ID> {
default void softDelete(T entity) {
Assert.notNull(entity, "The entity must not be null!");
Assert.isInstanceOf(SoftDeletableEntity.class, entity, "The entity must be soft deletable!");
((SoftDeletableEntity)entity).setIsDeleted(true);
save(entity);
}
default void softDeleteById(ID id) {
Assert.notNull(id, "The given id must not be null!");
this.softDelete(findById(id).orElseThrow(() -> new EmptyResultDataAccessException(
String.format("No %s entity with id %s exists!", "", id), 1)));
}
}
NOTE: If your application doesn't have the hard delete then you could add
String HARD_DELETE_NOT_SUPPORTED = "Hard delete is not supported.";
#Override
default void deleteById(ID id) {
throw new UnsupportedOperationException(HARD_DELETE_NOT_SUPPORTED);
}
#Override
default void delete(T entity) {
throw new UnsupportedOperationException(HARD_DELETE_NOT_SUPPORTED);
}
#Override
default void deleteAll(Iterable<? extends T> entities) {
throw new UnsupportedOperationException(HARD_DELETE_NOT_SUPPORTED);
}
#Override
default void deleteAll() {
throw new UnsupportedOperationException(HARD_DELETE_NOT_SUPPORTED);
}
Hope it could be useful.