JPA / Hibernate doubts fk relationship with criteria

paribe · **Joined:** Tue Jan 13, 2009 11:04 am **Posts:** 13

as doubts mount criteria which have the class to create User
teho and the criteria that relate to other class that has a fk

I am not able to make this relationship ...

podria someone help me ...

[code]

Criteria c = session.createCriteria (User.class);

C.add (Restrictions.eq ( "id", new Long (9)));
C.createAlias ( "Document", "doc");
c.add (Restrictions.eqProperty ( "doc.value", "0"));

List result = c.list ();
/ *
[/ code]

[code]

- classes created

class User (
id in private

)

class Document (
private int id
private String value
private int id_user
)

[/ code]

[code]
erro:
org.hibernate.QueryException: could not resolve property: ImsDocument of: br.com.certisign.ims.data.model.user.ImsUserImpl
[/code]

mmerder · **Posted:** Mon Jan 26, 2009 8:16 am

At class level, you should not use, for example, int-fields as foreign keys. You design your object-orientated model, which hibernate maps into a relational model. So your Document-class should look like this:

Code:

class Document (
  private int id;
  private String value;
  private User user;
)

paribe · **Joined:** Tue Jan 13, 2009 11:04 am **Posts:** 13

Now how do you relate the two objects:

- Because one is a list and another is an id

Someone would go for an example

Code:

class Document ( 
  private int id; 
  private String value; 
  @ManytoOne
  private User user; 
) 


class User 
id in private 
// add this list
@OnetoMany
List documents ;

mmerder · **Posted:** Tue Jan 27, 2009 6:23 am

I don't know, if I understand you right. With relate you mean, how to tell hibernate that Document.user and User.documents are the same association? If yes, then you could use mappedBy:

Code:

class User
id in private
// add this list
@OneToMany(mappedBy="user")
List documents ; 
}

Now, if you want to add documents to a user, you call user.getDocuments().add(..) and also document.setUser(...).

Take a look into the Annotation reference guide to see more examples how to map associations.