Bi-directional relationships and lazy initialization

meagle · **Joined:** Tue Aug 26, 2003 12:31 pm **Posts:** 14

Hibernate version: 2.1.6

I have a situation where I have a one-to-many bi-directional relationship like this (abbreviated):

Code:

A User class that has a lazy relationship to portlets:

<hibernate-mapping>
    <class
        name="com.matrix.portal.bo.user.Person"
        table="User"
        dynamic-update="false"
        dynamic-insert="false"
        discriminator-value="P"
    >

        <id
            name="id"
            column="User_ID"
            type="int"
            unsaved-value="0"
        >
            <generator class="native">
            </generator>
        </id>

        <set
            name="portlets"
            table="User_PFunc_Link"
            lazy="true"
            inverse="true"
            cascade="save-update"
            sort="unsorted"
        >
    </class>

</hibernate-mapping>

And a Portlet class that maps something like this:

<hibernate-mapping>
    <class
        name="com.matrix.portal.bo.PortletFunction"
        table="PortletFunction"
        dynamic-update="false"
        dynamic-insert="false"
        lazy="true"
    >
....
    </class>

When one side of the mapping is marked as lazy="true" then I can use Hibernate.initialize() to init the proxies. However, when I have both sides marked as lazy and I want to retrieve the collection from the parent object I have to do something like this:

Code:

// Init the collection
Hibernate.initialize(user.getPortlets());
user.getPortlets().size();
            
// Now init each element in the collection since it is marked as a proxy
Iterator iter = user.getPortlets().iterator();
while (iter.hasNext()) {
        PortletFunction element = (PortletFunction) iter.next();
        Hibernate.initialize(element);
}

Is this the best way to do this, or should it be avoided with a bi-directional relationship?

Regards,

Mark[/code]

anthony · **Posted:** Fri Oct 15, 2004 11:39 am

check fetch keyword using hql

meagle · **Joined:** Tue Aug 26, 2003 12:31 pm **Posts:** 14

Anthony,

I figured that would be the response. I use the fetch keyword in HQL statements for this purpose. I was concerned with code that looked like my example above where I retrieve collections that have elements that are proxies. Thanks for verifying what I needed to know.

Thanks,

Mark

meagle · **Joined:** Tue Aug 26, 2003 12:31 pm **Posts:** 14

Anthony,

Actually, this code:

Code:

StringBuffer sb = new StringBuffer(50);
sb.append("from User user inner join fetch user.portlets
  where user.lastName = 'Test'");
User user = (User)session.find(sb.toString()).get(0);

produces the same problem as my code in the first posting. Is there something I can do to fully initialize both sides of the relationship with an HQL statement. To reiterate this will get the collection, but the elements in the collection are not initialized. How can I use HQL to initialize the elements in the collection?

Regards,

Mark

anthony · **Posted:** Fri Oct 15, 2004 2:05 pm

this should work.... trace sql and look if the collection table appears in it

meagle · **Joined:** Tue Aug 26, 2003 12:31 pm **Posts:** 14

Anthony,

Sorry for the confusoin. This does work. I did not have my environment restarted properly.

Thanks,

Mark