Bi-directional one to many: PropertyValueException

sheldonh · **Joined:** Fri Dec 05, 2003 7:07 am **Posts:** 6

Hi folks,

I'm having trouble with a bi-directional one-to-many parent/child relationship, as discussed in Section 9 of the reference manual. I'm using hibernate-2.1rc1, and when I try to add a new child, I get this:

Code:

net.sf.hibernate.PropertyValueException: not-null property references a null or transient value: net.sf.hibernate.persister.EntityPersister.domain
   at net.sf.hibernate.impl.SessionImpl.checkNullability(SessionImpl.java:1206)
   at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:871)
   at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:815)
   at net.sf.hibernate.impl.SessionImpl.saveWithGeneratedIdentifier(SessionImpl.java:738)
   at net.sf.hibernate.impl.SessionImpl.save(SessionImpl.java:715)
   at net.sf.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:1317)
   at net.sf.hibernate.engine.Cascades$4.cascade(Cascades.java:114)
   at net.sf.hibernate.engine.Cascades.cascade(Cascades.java:436)
   at net.sf.hibernate.engine.Cascades.cascadeCollection(Cascades.java:526)
   at net.sf.hibernate.engine.Cascades.cascade(Cascades.java:452)
   at net.sf.hibernate.engine.Cascades.cascade(Cascades.java:503)
   at net.sf.hibernate.engine.Cascades.cascade(Cascades.java:482)
   at net.sf.hibernate.impl.SessionImpl.preFlushEntities(SessionImpl.java:2552)
   at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2192)
   at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2181)
   at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:61)
   at bz.clue.cluex4.daofactory.DataSource.commit(DataSource.java:42)
   ... 35 more

Here's my PostgreSQL 7.4 DDL:

Code:

CREATE TABLE Domain (
        Id              SERIAL PRIMARY KEY,
        Name         VARCHAR NOT NULL,
        CONSTRAINT      Domain_Name_ukey UNIQUE (Name)
);

CREATE TABLE Alias (
        Id              SERIAL PRIMARY KEY,
        LocalPart   VARCHAR NOT NULL,
        DomainId   INTEGER NOT NULL
                          CONSTRAINT Alias_DomainId REFERENCES Domain
                          ON DELETE CASCADE,
        CONSTRAINT      Alias_LocalPart_DomainId_ukey
                          UNIQUE(LocalPart, DomainId)
);

Here's the important stuff out of my Domain.hbm.xml and Alias.hbm.xml files:

Code:

<class name="bz.clue.cluex4.dao.Domain" table="Domain"
  dynamic-update="false"
  dynamic-insert="false">

    <id name="id" column="Id" type="java.lang.Long">
        <generator class="sequence">
            <param name="sequence">Domain_Id_seq</param>
        </generator>
    </id>
     ...
    <set name="aliases" lazy="true" inverse="true" cascade="all-delete-orphan">
        <key column="DomainId"/>
        <one-to-many class="bz.clue.cluex4.dao.Alias"/>
    </set>
</class>

<class name="bz.clue.cluex4.dao.Alias" table="Alias"
  dynamic-update="false"
  dynamic-insert="false">

    <id name="id" column="Id" type="java.lang.Long">
        <generator class="sequence">
            <param name="sequence">Alias_Id_seq</param>
        </generator>
    </id>
     ...
    <many-to-one name="domain" column="DomainId" not-null="true"/>
</class>

So now, as per Section 9, I have the following interesting classes and methods:

Code:

public class Alias implements DataAccessObject
{
    private Long id;
    private Domain domain;
    ...
    public void create()
    {
        domain.addAlias(this);
    }
    ....
}

public class Domain implements DataAccessObject
{
    private Long id;
    private Set aliases = new HashSet();
    ....
    public void addAlias(Alias alias)
    {
        alias.setDomain(this); // Not necessary in this use case, but the manual says do it
        getAliases().add(alias);
    }
}

I don't think the alias.setDomain(this) isn't necessary, because the caller is setting the domain property itself. But I stuck that in to conform with the manual.

So now in my calling code, I do this, where the DataSource class just encapsulates Session and Transaction functionality and the DomainFactory class's create() method encapsulates Session.save():

Code:

    DataSource.beginTransaction();
    Domain clue = new Domain();
    domain.setName("clue.bz");
    DomainFactory.create(clue);

    Alias root = new Alias();
    root.setLocalPart("root");
    root.setDomain(localhost);
    root.create();

    DataSource.commit();

The commit() fails with the exception given above, and it's the root.create() request that triggers it. Obviously, if I don't try to establish the parent/child relationship and persist the child, the commit() works.

I've read the Parent/Child section (9) very carefully, and I think I've followed it to the letter. I've checked the Users FAQ, the Latest FAQ from the Forums, and searched the old and current forum archives.

Any advice that could help me save what little hair I have left at this point would be greatly appreciated.

Thanks,
Sheldon.

emmanuel · **Posted:** Fri Dec 05, 2003 11:05 am

There is a buggy label in hibernate 2.1 and you exception should be
bz.clue.cluex4.dao.Alias.domain

However to your specific domain, try to reproduce in a simple real test case (one method) and give full source. The one you give are inconsistent

Code:

    DataSource.beginTransaction();
    Domain clue = new Domain();
    domain.setName("clue.bz"); //what is domain ? is it clue or not ?
    DomainFactory.create(clue); //what does this method do

    Alias root = new Alias();
    root.setLocalPart("root");
    root.setDomain(localhost); //what the hell is localhost ?
    root.create();

    DataSource.commit(); 