many-to-one not fetching "The One"

Encrypt · **Joined:** Thu Feb 09, 2006 12:37 pm **Posts:** 18

Hi all,
I have a problem, I have many problems, but right now the one hibernate problem I am having problems with, is that when I do a mapping from the child object to teh parent object (representing the one to many relationship in the DB) using the many-to-one property, the parent object isint fetched and thus when I try to use the parent object/property I get a null pointer exception.

Mapping documents:

Code:

   <class name="User" table="cmt_006_user">
      <id name="OID" column="OID" unsaved-value="null">
         <generator class="native"> 
         </generator>
      </id>      
      <version name="VID" column="VID" unsaved-value="negative" type="long"/>   
      <property name="updated" type="timestamp" column="Updated"></property>
      <property name="name" column="Name"></property>
      <property name="password" column="Password"></property>
      <property name="userRoleOID" column="UserRoleOID"></property>
      <property name="deleted" column="Deleted"/>
      <many-to-one name="userRole" class="com.orange.componentcatalogue.dm.UserRole" column="UserRoleOID" insert="false" update="false"/>
   </class>

The class User, has a UserRole property. I am trying to use the proerty thus:

Code:

if(!(user.getUserRole().getName().equals("admin")))

any ideas why this would happen? perhaps I am fundementally missing something?

Thanks
Gavin[/code]

himawan · **Joined:** Sat Aug 19, 2006 6:31 pm **Posts:** 139

How did the user get persisted to begin with? Was it assigned a userRole?

So you'd have to do user.setUserRole(role) and not only role.getUsers().add(user), for example, because the many side of the relationship is the one that manages the link.

Encrypt · **Joined:** Thu Feb 09, 2006 12:37 pm **Posts:** 18

Hi, I have now, i fouind that online last night amend my userRole mapping thus:

Code:

  <class name="UserRole" table="cmt_016_userrole">
      <id name="OID" column="OID" unsaved-value="null">
         <generator class="native"> 
         </generator>
      </id>      
      <version name="VID" column="VID" unsaved-value="negative" type="long"/>   
      <property name="updated" type="timestamp" column="Updated"></property>
      <property name="name" column="Name"></property>
      <property name="deleted" column="Deleted"/>
      
      <set name="users"  inverse="true" cascade = "all-delete-orphan" table="cmt_006_user">
         <key column="UserRoleOID"/>
         <one-to-many class="com.orange.componentcatalogue.dm.User"/>
      </set>
   </class>

However still getting the error, in the User class I have both get and set UserRole. In user role I have a set and get Users:

Code:

   public Set<User> getUsers()
   {
   return this._users;
   }
   
   public void setUsers(Set<User> users)
   {
   this._users = users;
   }

I didnt persist the row, as it is already in the DB, but I will be, although initial I didnt have the relationship mapping set up, which is what I am working on now.

So I am a bit lost, i admit i didnt realise i need to set up the many end, and I was dumb for not realising that, but the example I found is as above, and what you are saying, I think, is also consistant with the above.

Thanks
G[/code]

Encrypt · **Joined:** Thu Feb 09, 2006 12:37 pm **Posts:** 18

Actual I am stupid, the reason why I was still getting the null point was because I was using an un-persistered class I had put on the session.

Basicly the user logged in, so a create a User class to represent that user, check the users details in the DB if they match put user on the session. Thus tehre was no role associated with the user. How dumb!!!

No I am getting:
org.hibernate.LazyInitializationException: could not initialize proxy - the owning Session was closed

Encrypt · **Joined:** Thu Feb 09, 2006 12:37 pm **Posts:** 18

Sorted, I turned lazy loading off, and it works :)
bit of a hack? maybe, but it gets me to where I want to be, now I just have to make a choice of if I use springs inbuilt transactions for hibernate or OpenSessionInViewFilter/Interceptor or the HibernateInterceptor,

I am thinking the transactions, it seems more robust then trust myself :D

Thanks for all your help

G