I have a manytomany relation mapped with these 3 entities :
#Entity
public class ApplicatifDo {
.....
#OneToMany(cascade = CascadeType.ALL, mappedBy = "applicatifDo", fetch = FetchType.EAGER, orphanRemoval = true)
private Set<ApplicatifTerminalDo> applicatifTerminalSet;
.....
}
#Entity
public class ApplicatifTerminalDo {
......
#ManyToOne
#JoinColumn(name = "idApplicatif", nullable = false)
private ApplicatifDo applicatifDo;
#ManyToOne
#JoinColumn(name = "idTerminal", nullable = false)
private TerminalDo terminalDo;
#Column
private String remarques;
......
}
#Entity
public class TerminalDo {
......
#OneToMany(cascade = CascadeType.ALL, mappedBy = "terminalDo", fetch = FetchType.EAGER, orphanRemoval = true)
private Set<ApplicatifTerminalDo> applicatifTerminalSet;
......
}
I try to do many cascading tests on the join table ApplicatifTerminalDo from the two entities ApplicatifDo and TerminalDo. When I create or update a ApplicatifTerminalDo in the Set the cascading works well, but when it comes to orphanRemoval or delete It's not working
First :
For the delete I get the error :
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (`softtwo`.`applicatifterminal`, CONSTRAINT `FK_295tcnx7wjuvv5se1g3vldxxn` FOREIGN KEY (`idApplicatif`) REFERENCES `applicatif` (`id`))
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.Util.getInstance(Util.java:384)
.....
I would like that when I delete an entity ApplicatifDo or TerminalDo all rows related to them in the ApplicatifTerminal join table get deleted as well.
Second :
For the orphanRemoval, when I delete an element from the Set of ApplicatifTerminalSet in my ApplicatifDo entity and do a merge, then to test it I do a find by his Id of parent entity to get a new exact same entity and count the number of elements in the Set I get the good number (the number at the biginning with one less). But in my database I still have all my datas of my Set.
The code :
//My applicatifDo1 has 4 elements in the ApplicatifTerminalSet here
Assert.assertEquals(applicatifDo1.getApplicatifTerminalSet().size(), 4);
Iterator<ApplicatifTerminalDo> iterator = applicatifDo1
.getApplicatifTerminalSet().iterator();
boolean first = true;
while (iterator.hasNext()) {
ApplicatifTerminalDo element = iterator.next();
if (!first) {
element.setRemarques("remarques updated");
} else {
iterator.remove();
first = false;
}
}
// updateApplicatifDo do just a merge
applicatifDao.updateApplicatifDo(applicatifDo1.getId(), applicatifDo1);
ApplicatifDo applicatifDo = applicatifDao
.findApplicatifDo(applicatifDo1.getId());
Assert.assertEquals(applicatifDo.getApplicatifTerminalSet().size(), 3);
When I do that the update of setRemarques() works well. I have no error in the console when I do that. Then the remove seems to work because I retrieve the same object by his Id it still says I have 3 elements, then the fourth has been deleted : BUT, when I look in phpmyadmin my 4 elements/relations in my appplicationterminal table are still there.
If I do another TestNg later, just retrieving my applicatifDo by his Id this time it gets the four elements.
Then there a big integrity problem here, and still I always use eagerly fetching. Any idea why such problem here ? And how could I make my cascading works ?
Third :
More globally, I have another cascading + orphanRemoval rules on other two entities and that works very well, but the entity target of these cascades does not have other relations with other entities.
Clearly, there is specific rules (or maybe limitations) when cascading on entities with other relationships.
Please do you know tutorials/rules explaining the best practices for such mappings ?
Thanks in advance. I'm stuck on this for too long.
Related
Let´s assume these two entities:
#Entity
public class MyEntity {
#Id private String id;
#OneToMany(mappedBy = "myEntity", cascade = ALL) private Set<MyEntityPredecessor> predecessors;
}
#Entity
public class MyEntityPredecessor{
#Id private String id;
#ManyToOne(name = "entityID", nullable = false) private MyEntity myEntity;
#ManyToOne(name = "entityPre", nullable = false) private MyEntity predecessor;
}
When I try to call a delete with Spring Boot Data (JPA) with a MyEntity Instance, it will work some times (I see the select and then the delete statements in correct order), but sometimes it will try to run an update on the second entity trying to set the "entityPre" Field to null (even thoug it is set to nullable=falsE), causing the DB to send an error (null not allowed!! from DB constraint).
Strangely, this will happen at "random" calls to the delete...
I just call "myEntityRepository.getOne(id)", and then myEntityRepository.delete() with the result... There is no data difference in the DB between calls, the data structure has no null values when calling the delete method, so that should not be the reason.
Why is JPA sometimes trying to call updates on the Predecessor Table, and sometimes directly deleting the values? Am I missing something?
Add a similar ManyToOne annotated set to MyEntity which refers to the other non-nullable property, like:
#OneToMany(mappedBy = "predecessor", cascade = ALL) private Set<MyEntityPredecessor> other;
some explanation:
The issue doesn't happen randomly, but happen when you try to delete an entity which is linked to one (or more) MyEntityPredecessor via the predecessor property (which is mapped to the entityPre field)
Only the other field (entityID) is mapped back to the MyEntity object, so the deletion-cascade only happens via by that field.
I'm writing some entity relationships using Spring Data and Java. I have this pair of classes (edited):
Subject:
#Entity
#Table(name = "SUBJECT")
// Lombok, etc., attributes removed
public class Subject {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
#Column(name = "ID", updatable = false, nullable = false)
#JsonProperty("id")
private Long id;
#OneToMany(targetEntity = SubjectResource.class, mappedBy = "subject", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
private List<SubjectResource> resources;
}
SubjectResource:
#Entity
#Table(name = "SUBJECT_RESOURCE")
// Lombok, etc., attributes removed
public class SubjectResource {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
#Column(name = "ID", updatable = false, nullable = false)
private Long id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "SUBJECT_ID")
private Subject subject;
}
I'm trying to solve these issues:
Question 1: Can I manipulate #OneToMany or #ManyToOne to NOT have the child class recurse its parent?
Fetch of resources returns subject data:
/subject/101:
{"id":101,"resources":[{"id":1001,"subject":101},{"id":1002,"subject":101},{"id":1003,"subject":101},{"id":1004,"subject":101}]}
/subjectResource/1001:
{id:1001,subject:{"id":101,"resources":[{"id":1001,"subject":101},{"id":1002,"subject":101},{"id":1003,"subject":101},{"id":1004,"subject":101}]}}
That is, /subjectResource/1001 returns its ID and the entire /subject/101 query.
How can I have just the subjectResource data, without its parent?
Question 2: Through #OneToMany or #ManyToOne can I get Hibernate to fetch on a "1" (O(1)) basis?
When /subjects does its thing, it works with Hibernate on a "n+1" (O(n)) basis: 1 fetch of subjects, n fetches of resources, one for each subject ID.
I could force a single fetch through a fancy repository #Query annotation ("select s from subject s left join fetch s.resources"). But that means putting the subject : subject_resource definitions in two places, etc.
Can JPA implementation / Hibernate be forced to do a join, and thus make only one database call, through annotation within an entity class?
Question 3: How do I get my Spring Data / Spring Repository to cooperate with Ignite, and have the cache return the data it already had on the first call?
I'm usng FetchType.LAZY, as all good pupils do. I'm also storing things in Apache Ignite. For /subject/101 the initial call fetches everything OK, returning it in JSON. But the second call gets from the Ignite cache, which complains about being out of transaction.
How do get my LAZY fetches to cooperate with Ignite?
Thanks,
Jerome.
It seems I have a problem with OneToMany, ManyToOne mapping.
I'm using a CrudRepository named "ur" here:
ur.save(new User("zx","z", "a", "email#email.com", "Baa")); //userRepo save
User u1 = ur.findOneByUserName("Bx");
MyToken t1 = new MyToken("X5");
u1.addToken(t1);
ur.save(u1);
MyToken t2 = TokenRepo.findOneByToken("X5"); // a different crudRepository
String foundUser = t2.getUser().getUserName(); // THIS "user" is null.
relevant sections of User.java (extends AbstractPersistable<Long>):
#OneToMany(fetch = FetchType.EAGER, cascade={CascadeType.ALL}, mappedBy = "user")
private Set<Role> roles = new HashSet<Role>(1);
#OneToMany(fetch = FetchType.EAGER, cascade={CascadeType.ALL}, mappedBy = "user")
private Set<MyToken> token = new HashSet<MyToken>();
MyToken.java (extends AbstractPersistable<Long>):
#ManyToOne(fetch = FetchType.EAGER, cascade={CascadeType.ALL})
#JoinColumn(name="user") // commenting this out or not does nothing...
private User user;
My debugger says 'user' is 'null' at line "String foundUser" even though that should be completely false according to the code.
As you can see, all is "eager" so I don't see why MyToken.setUser() is not automatically done. How are they not linked already? AnyInitiatedToken.getUser() should not be null if you already did User.addToken, and UserRepo.save().
NOTE: I have also tried .LAZY for the MyToken.java and Role.java class (but still doesn't work).
Since you did not post the setters, I gonna assume they look like default setter.
User.token is set, but it has a mappedby, so it is really irrelevant for what is stored in the DB. Token.user matters, but that is still an NULL so that's what get's saved and retrieved.
You have two options:
Change User.setToken() to update Token.user of the passed in Token (and of the one that was previously set.
Whenever you call User.setToken() also update Token.users to make both directions of the relationship match.
I think it's not related to the fetch strategy whether it's eager or lazy fetch type. I think you gave column alias for the user's id and missed that the name atributte's value of the #JoinColumn should reference that primary key column alias.
Like in the User you have:
#Id
#Column(name = "userid", unique = true, nullable = false)
public String getUserId() {
return this.userId;
}
then in the Token should be
#ManyToOne(fetch = FetchType.EAGER, cascade={CascadeType.ALL})
#JoinColumn(name="userid") // commenting this out or not does nothing...
private User user;
Here are my entities:
#Entity
public class Actor {
private List<Film> films;
#ManyToMany
#JoinTable(name="film_actor",
joinColumns =#JoinColumn(name="actor_id"),
inverseJoinColumns = #JoinColumn(name="film_id"))
public List<Film> getFilms(){
return films;
}
//... more in here
Moving on:
#Entity
public class Film {
private List actors;
#ManyToMany
#JoinTable(name="film_actor",
joinColumns =#JoinColumn(name="film_id"),
inverseJoinColumns = #JoinColumn(name="actor_id"))
public List<Actor> getActors(){
return actors;
}
//... more in here
And the join table:
#javax.persistence.IdClass(com.tugay.sakkillaa.model.FilmActorPK.class)
#javax.persistence.Table(name = "film_actor", schema = "", catalog = "sakila")
#Entity
public class FilmActor {
private short actorId;
private short filmId;
private Timestamp lastUpdate;
So my problem is:
When I remove a Film from an Actor and merge that Actor, and check the database, I see that everything is fine. Say the actor id is 5 and the film id is 3, I see that these id 's are removed from film_actor table..
The problem is, in my JSF project, altough my beans are request scoped and they are supposed to be fetching the new information, for the Film part, they do not. They still bring me Actor with id = 3 for Film with id = 5. Here is a sample code:
#RequestScoped
#Named
public class FilmTableBackingBean {
#Inject
FilmDao filmDao;
List<Film> allFilms;
public List<Film> getAllFilms(){
if(allFilms == null || allFilms.isEmpty()){
allFilms = filmDao.getAll();
}
return allFilms;
}
}
So as you can see this is a request scoped bean. And everytime I access this bean, allFilms is initially is null. So new data is fetched from the database. However, this fetched data does not match with the data in the database. It still brings the Actor.
So I am guessing this is something like a cache issue.
Any help?
Edit: Only after I restart the Server, the fetched information by JPA is correct.
Edit: This does not help either:
#Entity
public class Film {
private short filmId;
#ManyToMany(mappedBy = "films", fetch = FetchType.EAGER)
public List<Actor> getActors(){
return actors;
}
The mapping is wrong.
The join table is mapped twice: once as the join table of the many-to-many association, and once as an entity. It's one or the other, but not both.
And the many-to-many is wrong as well. One side MUST be the inverse side and use the mappedBy attribute (and thus not define a join table, which is already defined at the other, owning side of the association). See example 7.24, and its preceeding text, in the Hibernate documentation (which also applies to other JPA implementations)
Side note: why use a short for an ID? A Long would be a wiser choice.
JB Nizet is correct, but you also need to maintain both sides of relationships as there is caching in JPA. The EntityManager itself caches managed entities, so make sure your JSF project is closing and re obtaining EntityManagers, clearing them if they are long lived or refreshing entities that might be stale. Providers like EclipseLink also have a second level cache http://wiki.eclipse.org/EclipseLink/Examples/JPA/Caching
I have two entity classes user and device.
User entity:
public class User {
private Long userId;
#OneToMany( mappedBy = "userId", fetch = FetchType.LAZY)
private Collection<Device> deviceCollection;
and device entity:
public class Device implements Serializable {
#JoinColumn(name = "user_id", referencedColumnName = "user_id")
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private User userId;
When I merge a previously detached device entity into the entity manager after the parent user has been deleted, both the (previously removed) user and the device are re-inserted into the database. There is no cascade annotation on user or device entity; therefore, I don't expect the user entity to be reinserted but it did;
How do I prevent the merge operation to cascade to the user entity?
Thanks in advance.
Any changes you do in detached state there is no possible way for Session Manager to know it so for it the changes are always new objects that needs to be merged (If you are calling merge)
So when you call merge it will load it from database so your object will have Prev+ new changes. So that is why mentioned behavior is happening.
What you can do is first load entity in the session apply changes and then call merge.
What you can do is something like below I have used similar relationship in one of my project with Eclipse Link
Query query = entityManager
.createNamedQuery("User.FindByUserId");
User fromDatabase = null;
try {
query.setParameter("userId", device.getUser().getUserId());
fromDatabase = (User) query.getSingleResult();
} catch (NoResultException noResultException) {
// There is no need to do anything here.
}
if (fromDatabase == null) {
User user= entityManager.merge(device.getUser());
device.setUser(user);
} else {
device.setUser(user);
}
entityManager.persist(device);
Try adding insertable=false, updatable=false to your JoinColumn, e.g.
#JoinColumn(name = "user_id", referencedColumnName = "user_id", insertable=false, updatable=false)
You should be using a version number to prevent entities from being mistakenly resurected. This will force an exception, where as the specification is a bit unclear on what should happen when merging over a relation that isn't marked cascade all or merge. The spec states that managed entities will be synchronized to the database, while the section dealing with merge implies that even entities referenced by relations without the cascade merge/all options will be managed afterward. This behavior is probably not what was intended, but shouldn't be relied on until clarified.
I had the same problem
and I found a bug about this: EntityManager.merge() cascading by default
but I really don't understand why this behaviour was never fix. It is one of reasons among others that I don't use EclipseLink (But it's not the point here)
Edit:
Chris, the comment which begin with "I'm not an expert" the argument that is put in head is not right, I think. What I understand, it's just that entity with a relation without cascade=MERGE or cascade=ALL, you can just navigate, that's all.
Otherwise why use Merge annotation ? It doesn't make sense.