ManyToOne « Map « JPA Q&A





1. Two collections manyToOne to same primary key    stackoverflow.com

I'm coding a web page in Hibernate-JPA and Oracle. I need the following: I have two classes: Place and Home. I need two collections of type Place in every Home: I do ...

2. JPA - manytoone cascading    stackoverflow.com

I've got two entities ServiceDownload.java

@Entity
public class ServiceDownload implements Serializable {
    private static final long serialVersionUID = -5336424090042137820L;

@Id
@GeneratedValue
private Long id;
@Length(max = 255)
private String description;

private byte[] download;

private String fileName;

@ManyToOne
private Service service;
Service.java
@Entity
public ...

3. hibernate ManyToOne why 2 queries are generated instead of one?    stackoverflow.com

MyTable is a table in my Oracle DB, it has a CMP_ID to join the COMPANIES table. Here is the Java implementation :

public class MyTable implements Serializable {
...
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumns( { @JoinColumn(name ...

4. Why does TypedQuery.getResultList() resolve every ManyToOne association with a seperate SELECT?    stackoverflow.com

Considering the following simple entity association: (EntityA) *-1 (EntityB) made in database with a foreign key in EntityA (entityB_id). The JPA Entities are mapping this relationship unidirectional:

@Entity
EntityA {
    @Id
   ...

5. JPA persist object in a ManyToOne relationship    stackoverflow.com

I have a company/employee @OneToMany relation in my database defined as:

@Entity
public class Employee {
   @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
   private long id;
   @ManyToOne @JoinColumn(name="companyid")
   Company company;
 ...

6. Hibernate ManyToOne insert, then update    stackoverflow.com

I have 4 entities: Person ---> FooRole <---- PersonAtOrg ------> Org Person has a OneToOne with FooRole PersonAtOrg has a @ManyToOne for FooRole and Org. I lookup a Person that has a FooRole. ...

7. JPA How to create Query with ManytoOne relationship?    stackoverflow.com

The basic question:
If I have an entity B with ManyToOne field x linked to another entity A, how do I get all the instances of B that have A ...

8. Writing HQL Query for ManyToOne Association    stackoverflow.com

Hii, I have two entities with bidirectional association. Project.java

class Project{

    int project_id;

    @OneToMany(mappedBy="project")
    private Set<Users> projectsUsers = new HashSet<Users>();

    //getters ...

9. multiple ManyToOne in JPA: updating/creating references    stackoverflow.com

(I'm a newbie in JPA) I have 3 JPA entities: User, Setting and UserSetting.
The relations are: ManyToOne between UserSetting, User; ManyToOne between UserSetting, Setting. The purpose is: when adding an entry to UserSetting, an ...





10. JPA: delete object from ManyToOne relationship doesn't update a parent collection    stackoverflow.com

I have ManyToOne relationship between Parent and Child. I want to Delete multiple Child entities that answer a certain query. The problem is that after I run a Delete query, Parent.getChildren() ...

11. ManyToOne Hibernate a foreign key that doesnt have the same name in the two tables    stackoverflow.com

I did extensive research, but without success .. I have two tables: entité and reference. with fields of entity: id_entite, attribut1, attribute2, attribut3 fields of reference: num_reference, description_reference Now the data: ...

12. Get ManyToOne Entity from other Entity properties    stackoverflow.com

I have an entity structure that looks like this:

@Entity
public class Event {
     @Id
     private Long id;
     @ManyToOne
   ...

13. Hibernate - Cascading problems using ManyToOne association    coderanch.com

Hello, I am working with Hibernate trying to get ManyToOne working. But problems of course since I am here... I am working with two classes (Tables) 1. Users 2. Incident The users are unique and the identifier is "email". One user can have multiple incidents but one incident can only have one user. Though it is not a bi-directional relation, incident ...

14. JPA ManyToOne Mapping Question    coderanch.com

Hi Experts, I have a situation where i have two entities namely Event and Employee. The Event entity has a ManyToOne relation with the Employee. For a given Date, there is a single record of event for an employee. Now, when i use employee.getEvents() , the list will be enormous . Say after 5 year will have 5*365 records for an ...

15. ManyToOne - Mapping problem (Old DB)    forum.hibernate.org

Hello together, I have a problem with the @ManyToOne mapping. I get this exception: No row with the given identifier exists: [hibernate.data.OperatorDB#0] I have to say that bevor of using Java and Hibernate there was a C-ODBC solution, that could not handle null fields in the DB, so they decided to make all Fields 'not null' and wrote a 0 instead ...

16. Create new ManyToOne Entities    forum.hibernate.org

Hello! Simple question: I have two tables, table1 and table2. table1 has one column table2id. Now I want to create a new entry in table1. Table1 t1 = new Table1(); Table2 just holds a status: Table2 t2 = new Table2(); t2.setId(1); t1.setTable2(t2); ...save... Well, sometimes this scenario works, sometimes not. In my case it just works for table id 1. If ...





17. ManyToOne and Delete    forum.hibernate.org

Hello, i have to classes A und B they have a ManyToOne dependency . If i delete A , all b objects should be delete too. How can I do this? Code: public class B{ @ManyToOne(cascade = {CascadeType.ALL}) @Override public A getA() { return a; ...

18. A simple ManyToOne association and a delete    forum.hibernate.org

I have two classes User and Product. A Product has a unidirectional ManyToOne association to a User. Now a User instance is being deleted. I would like to know what are the possibilities for Hibernate to update the Product instances that references that specific user. Can I automatically set the association to null? Can I automatically delete the user? Or do ...

19. ManyToOne relationship and Property using same column    forum.hibernate.org

Im working with a legacy database and an application written for Apple WebObjects and migrating it to Hibernate. I'm trying to map a many to one relationship and its join column as a property. But Hibernate gives "Repeated column in mapping" error if i try to do that, unless i make one of them readonly with insert=false and update=false. But the ...

20. ManytoOne not working    forum.hibernate.org

Why doesnt the following work versions hibernate-annotations-3.4.0.GA hibernate-distribution-3.3.2.GA hibernate-entitymanager-3.4.0.GA hibernate-validator-4.0.1.GA mysql-5.1.41-linux-i686-glibc23 I have entities as follows: Person, Gender, Title Person has gender_id and title_id as foreign keys, with foreign indexes set up to gender and title tables The only way i can insert a Person row is to populate persons Gender and Title attributes with rows read from the Gender and ...

21. Problem with refresh ManyToOne relationship in session    forum.hibernate.org

this.session = HibernateUtil.pegarSessao(id); this.tx = this.session.beginTransaction(); return this.session .createQuery("from Contact WHERE customer.id = ?") .setInteger(0, customer.getId()) ...

22. ManyToOne Relationship Causing A New Object To Be Created    forum.hibernate.org

Hi, I have a strange situation, not sure if anyone has seen this before, but I have a transient object, A, and want to set the relationships on this object, so I set the ManyToOne relationship by using the set method for B, and then I ensure that B has an instance of A in its collection of A, but when ...

23. Unable to create ManyToOne relationship succesfully    forum.hibernate.org

Hi All, I'm trying to get started with Hibernate and JPA. I want to create a ManyToOne relationship between two Java objects. I'm not using any configuration XML files. I'm doing this all programmatically. I'm using the following code for configuring my Hibernate: Code: AnnotationConfiguration configuration = new AnnotationConfiguration(); configuration.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver"); ...

24. How to use ManyToOne to look up by other column first?    forum.hibernate.org

Hi, I'm wondering if it's possible to use a ManyToOne annotation to 'find or create' on the reference table. Code: class Foo { @ManyToOne(fetch=FetchType.EAGER) @JoinColumn(name = "reference_table_id") ReferenceTable referenceTable; ... } class ReferenceTable { @Id @GeneratedValue @Column(name = "id") Integer ...

25. ManyToOne on existing entity    forum.hibernate.org

Hi All, Have a static table of content types with data similar to below: content_type, description application/XML, XML Document image/jpeg, JPeg Image Described below as: Code: @Entity @org.hibernate.annotations.Entity(mutable = false) @org.hibernate.annotations.AccessType("field") @Table(name = "CONTENT_TYPE") public class ContentType { @Id @Column(name = "content_type", updatable = false, insertable = false) private String contentType; ...

26. ManyToOne non primary key - sequential select    forum.hibernate.org

I have a ManyToOne from entity A to entity B on a non primary unique key. If I annotation the association with @LazyToOne and use build time instrumentation, I can get it to be loaded lazily. The problem I'm having is if I create a criteria query that does a join for this assoication, whenever I go to access entity B ...

28. ManyToOne join column from other assocations    forum.hibernate.org

Newbie Joined: Thu Nov 24, 2011 1:47 pm Posts: 3 Hello everyone. First question here. I want to make a mapping that look like this: Code: @Entity public class Event { @Id private Long id; @ManyToOne private Device device; ...

29. Multiple ManytoOne mappings, join column    forum.hibernate.org

In my code I am using two ManytoOne mappings as follows: @JoinColumn(name = "Prompt_id", referencedColumnName = "Id", nullable = false) @ManyToOne(optional = false) private Prompt promptid; @JoinColumn(name = "Variable_id", referencedColumnName = "Id", nullable = false) @ManyToOne(optional = false) private Variable variableid; Prompt and Variable are tables with PK as Id in both. I am using them in a CallFlowMaster entity where ...

30. Inheritance and ManyToOne link    forum.hibernate.org

@Entity @Inheritance(strategy = InheritanceType.JOINED) public abstract class PathElement extends CoreBase { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private long id; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "parentPathElementId") private PathElement parentPathElement; @OneToMany(mappedBy = "parentPathElement", cascade = {CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.LAZY) private List subPathElements = new ArrayList(); ...

31. Problem with two optional ManyToOne mappings    forum.hibernate.org

Newbie Joined: Fri Feb 23, 2007 12:04 am Posts: 3 I'm having trouble when I try to persist objects of a class referencing two other persistence classes, either of which is always null. The class Counseling (a scheduled event for a user to either talk to a specific customer or do some other tasks) is referencing, as ManyToOne, both a Candidate ...

32. CompositeID with ManyToOne    forum.hibernate.org

Newbie Joined: Sun Feb 25, 2007 1:35 pm Posts: 5 Hello everybody, I've got a little problem using composite ID when refering in a ManyToOne association. In my application there are sites where the ID consists only of the name: Code: @Entity public class PokerSite { @Id private String siteName; ...

33. ManyToOne using join field and annotations?    forum.hibernate.org

I think this may not be possible with the current JPA annotations, but just wanted to confirm. I have a ManyToOne Child->Parent relationship that is not via a foreign key but instead via a shared identifier that happens to be unique on the Parent. 1) Is there any way to map this using the JPA annotations? 2) If not, is it ...

34. Named Query on a ManyToOne mapped table    forum.hibernate.org

Hi, I am getting error while doing a findAll query on a table(Message - in my case) that has a foreign-key relationship with another table (Department). When I execute findall, it is mapping a String instead of Department object. How I have to define the NamedQuery in this case? Code: @NamedQueries({ @NamedQuery( ...

35. IdClass instead of Entity in ManyToOne relationship    forum.hibernate.org

Hi, I want a many to one relationship however I want the IdClass object instead of the actual entity object. synthetic example: @Entity @IdClass(PlanetPk.class) class Planet { } @Entity class Ship { @ManyToOne PlanetPk homeWorld; } Why: I do not want to manage lazy loading and detached objects. I want to force the retrieval of the object in all scenarios by ...

36. Optional ManyToOne    forum.hibernate.org

Newbie Joined: Wed Dec 17, 2008 6:38 am Posts: 4 Hi everyone, I have a problem with ManyToOne relations with optional parameter set to true. I have a Project entity that contains a ManyToOne optional relationship to a ProjectEVA entity. Also I have another entity called ProjectBaseline that has a many to one relationship with Project. Now, I have the following ...

37. Problem with ManyToOne cascade delete    forum.hibernate.org

Newbie Joined: Fri Mar 27, 2009 7:09 am Posts: 3 Hi, I am using Hibernate core 3.2.6 and hibernate annotations 3.3.0 with spring and struts and MySQL 5.0 . I have problem with ManyToOne annotation. If I have for example table which looks like the one below... and I want to delete Employee with id=4 I cant do it...cuz this row ...

38. ManyToOne cascade doesnt work    forum.hibernate.org