Spring boot. How to properly remove @ManyToOne child collection

Question

Have a "should be" strange question, but how to properly handle the case, when I have a parent and a child:

@Entity
public class Parent {
   @Id
   private long id;

   @OneToMany(mappedBy = "parent")
   @Cascade(values = {CascadeType.PERSIST, CascadeType.REMOVE});// mysql db
   private List<Child> children = new LinkedList<Child>();// yea, this can be removed
}


@Entity
public class Child {
   @Id
   private long id;

   @ManyToOne
   @JoinColumn
   private Parent parent;
}

And here is what I'm generally attempting to do:

public class SomeService {
    @Autowired
    private ParentDao parentDao;

    @Autowired
    private ChildDao childDao;

    @Transactional
    public void removeChildren(Parent parent) {
        // attempts #1
        childDao.removeAll(parent.getChildren());

        // attempts #2
        for(Child ch: parent.getChildren()) {childDao.removeById(ch.getId());}

        // attempts #3
        parent.getChildren().clear();
        parentDao.save(parent);
   }

With hibernate sql logging enabled, I see that none of the upper attempts even try to make a delete statement - only "select ... from parentTable". And, of course, all of the entries remain.

DAOs are extending from JpaRepository<Parent\Child, Long>.

For the "Id" case I even tried verifying the existing entry by id, and yes - the entry existed.

This I have with both "1.4.1 RELEASE" and "2.1.4 RELEASE" versions of the Spring Boot. Can someone tell me what am I doing wrong? (Deleting a parent works and cascade works as it should for removing).

Example with output:

@Override
    @Transactional
    public void cleanResourcesForParent(SessionConfig cfg) {
        logger.info("Removing resources for parent {}", cfg);

        for (Resource r : cfg.getResources()) {
            logger.info(">>> {}", r);
            logger.info("exist? {}", resourceDao.existsById(r.getId()));
            logger.info("Attempt 1");
            resourceDao.deleteById(r.getId());
            logger.info("Attempt 2");
            resourceDao.delete(r);
        }
        logger.info("Attempt 3");
        resourceDao.deleteAll(cfg.getResources());

        logger.info("flush");
        resourceDao.flush();
        /*
         * cfg.getResources().clear(); sessionConfigDao.saveAndFlush(cfg);
         */
    }

Parent - SessionConfig, child - Resource (mapped as session_config_resource at the DB).

Output:

Hibernate: select resources0_.parent_id as parent_i3_10_0_, resources0_.id as id1_10_0_, resources0_.id as id1_10_1_, resources0_.line as line2_10_1_, resources0_.parent_id as parent_i3_10_1_ from session_config_resource resources0_ where resources0_.parent_id=?
2019-04-12 14:35:35 INFO  [scheduling-1] SessionConfigServiceImpl.resolveSessionConfig: Updating C:\IpPhoneAutomation\ATA\ConfigSession\GLAnton\Sanity450LyncContactPictureConfig.tcl. Sync file date: 1545995407645, file last modif: 1545995407645
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Removing resources for parent SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6]
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1097, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=0]
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
Hibernate: select resource0_.id as id1_10_0_, resource0_.line as line2_10_0_, resource0_.parent_id as parent_i3_10_0_, sessioncon1_.id as id1_9_1_, sessioncon1_.config_name as config_n2_9_1_, sessioncon1_.modified as modified3_9_1_ from session_config_resource resource0_ left outer join session_config sessioncon1_ on resource0_.parent_id=sessioncon1_.id where resource0_.id=?
Hibernate: select resources0_.parent_id as parent_i3_10_0_, resources0_.id as id1_10_0_, resources0_.id as id1_10_1_, resources0_.line as line2_10_1_, resources0_.parent_id as parent_i3_10_1_ from session_config_resource resources0_ where resources0_.parent_id=?
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:35 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1098, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=1]
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1099, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=2]
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1100, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=3]
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1101, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=4]
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: >>> Resource [id=1102, parent=SessionConfig [id=1096, configName=Sanity450LyncContactPictureConfig.tcl, modified=1545995407645, resources=6], line=5]
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: select count(*) as col_0_0_ from session_config_resource resource0_ where resource0_.id=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: exist? true
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 1
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 2
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: Attempt 3
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
2019-04-12 14:35:36 INFO  [scheduling-1] ResourceService.cleanResourcesForParent: flush
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: insert into session_config_resource (line, parent_id, id) values (?, ?, ?)
Hibernate: delete from session_config_resource where id=?
Hibernate: delete from session_config_resource where id=?
2019-04-12 14:35:36 INFO  [scheduling-1] SessionConfigServiceImpl.cacheSessionConfigData: Done

Can you paste the piece, where the invokation of `removeChildren` is? — Andronicus, Apr 12 '19 at 11:27
resourceDao.delete(entity) tries to do something, but the result remains the same. — Draaksward, Apr 12 '19 at 11:39
Possible duplicate of [JPA OneToMany not deleting child](https://stackoverflow.com/questions/2011519/jpa-onetomany-not-deleting-child) — Tom, Apr 12 '19 at 11:41
The cleanResourcesForParent is invoked by a service, which doesn't have any transactions or additional flags. Just a regular Service.method, which is triggered by @Scheduled — Draaksward, Apr 12 '19 at 11:45
Well, I think I'll need to return to my basic Spring JPA reading, because setting the "orphan removal" flag in the parent, and simply doing a "getResource().clear()" with a submit of the parent finally made it work correctly. Thanks for all your help. — Draaksward, Apr 12 '19 at 11:53

score 0 · Answer 1 · answered Apr 12 '19 at 11:56

And the culprit (believe I misunderstood the purpose of the flag) was the "orphan removal" option, marked from the Parent:

 @OneToMany(mappedBy = "parent", orphanRemoval = true)
   @Cascade(values = {CascadeType.PERSIST, CascadeType.REMOVE});
   private List<Child> children = new LinkedList<Child>();

Allowing to:

parent.getChildren().clear(); 
parentDao.saveAndFlush(parent);

to finally put an end to this issue.

Spring boot. How to properly remove @ManyToOne child collection

1 Answers1