inheritance problem does not allow NULLs

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

I have big trouble setting up an inheritance relation for use with J2SE/EJB3.

I have created a Person and an Employee extending the person.
The Person has an auto filled in ID and the Employee inherits that. I have not yet found any examples that cover this.

There are probably better ways to do this (without inheritance), but I'm looking for the limits and want to know how inheritance is supported by Hibernate EJB3.

Person

Code:

package domain;

import java.util.Date;
import javax.persistence.*;

/**
 * 
 */
@Entity
@Inheritance(strategy=InheritanceType.JOINED)
public class Person
{
    protected Long id;
    protected String name;
    protected String firstname;
    protected String street;
    protected String city;
    protected String country;

    @Temporal(TemporalType.DATE)
    protected Date birth;

    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    public Long getId()
    {
        return id;
    }
//and more get() and set()-ers

Employee

Code:

package domain;

import javax.persistence.Entity;
import javax.persistence.ManyToOne;

@Entity 
public class Employee extends Person {
    
   protected Department department;
    
   
    @ManyToOne
    public Department getDepartment()
    {
      return department;
     }

     public void setDepartment(Department dep)
     {
      this.department = dep;
     }
}

Hibernate version:
Hibernate 3.1.2
Entitymanager 3.1beta6
Annotations 3.1beta8
Mapping documents:

Code between sessionFactory.openSession() and session.close():

Code:

emf = Persistence.createEntityManagerFactory("manager1", new HashMap())
emf.createEntityManager();
EntityTransaction tx = emf.getTransaction();                       
tx.begin();
        
        Department dep = new Department();
        dep.setName("Boekhouding");
        
        Employee pietje = new Employee();
        Calendar cal = Calendar.getInstance();
        cal.set(1980, 12, 5);
        pietje.setBirth(cal.getTime());
        pietje.setFirstname("Piet");
        pietje.setName("Vennema");
        pietje.setCity("Veenendaal");
        pietje.setStreet("Dorpsstraat 62");
        pietje.setCountry("NL");
        
        //department
        pietje.setDepartment(dep);
        dep.addEmployeeToPayroll(pietje);
                
        em.persist(pietje);
        
tx.commit();

Full stack trace of any exception that occurs:
java.sql.SQLException: Cannot insert the value NULL into column 'PERSON_ID', table 'test.test.Employee'; column does not allow nulls. INSERT fails.
at net.sourceforge.jtds.jdbc.SQLDiagnostic.addDiagnostic(SQLDiagnostic.java:365)
at net.sourceforge.jtds.jdbc.TdsCore.tdsErrorToken(TdsCore.java:2781)
at net.sourceforge.jtds.jdbc.TdsCore.nextToken(TdsCore.java:2224)
at net.sourceforge.jtds.jdbc.TdsCore.getMoreResults(TdsCore.java:628)
at net.sourceforge.jtds.jdbc.JtdsStatement.processResults(JtdsStatement.java:525)
at net.sourceforge.jtds.jdbc.JtdsStatement.executeSQL(JtdsStatement.java:487)
at net.sourceforge.jtds.jdbc.JtdsPreparedStatement.executeUpdate(JtdsPreparedStatement.java:421)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2065)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2407)
at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:37)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:243)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:269)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101)
at org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:131)
at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:87)
at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:38)
at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:642)
at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:616)
at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:620)
at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:127)
at EJB3Test.go(EJB3Test.java:74)
at EJB3Test.main(EJB3Test.java:29)
WARN - SQL Error: 515, SQLState: 23000
ERROR - Cannot insert the value NULL into column 'PERSON_ID', table 'test.test.Employee'; column does not allow nulls. INSERT fails.
Name and version of the database you are using:
Microsoft SQL 2000 SP 4
The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:
DEBUG - begin
DEBUG - opening JDBC connection
DEBUG - total checked-out connections: 1
DEBUG - opening new JDBC connection
DEBUG - created connection to: jdbc:jtds:sqlserver://localhost/test, Isolation Level: 2
DEBUG - current autocommit status: true
DEBUG - disabling autocommit
DEBUG - after transaction begin
DEBUG - Transaction activated, move to FlushMode AUTO
DEBUG - setting flush mode to: AUTO
DEBUG - transient instance of: domain.Employee
DEBUG - saving transient instance
DEBUG - saving [domain.Employee#<null>]
DEBUG - executing insertions
DEBUG - id unsaved-value strategy UNDEFINED
DEBUG - Getting current persistent state for: [domain.Department#Boekhouding]
DEBUG - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG - select department_.name from Department department_ where department_.name=?
Hibernate: select department_.name from Department department_ where department_.name=?
DEBUG - preparing statement
DEBUG - binding 'Boekhouding' to parameter: 1
DEBUG - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG - closing statement
DEBUG - Inserting entity: domain.Employee (native id)
DEBUG - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG - insert into Person (birth, city, firstname, street, name, country) values (?, ?, ?, ?, ?, ?)
Hibernate: insert into Person (birth, city, firstname, street, name, country) values (?, ?, ?, ?, ?, ?)
DEBUG - preparing statement
DEBUG - Dehydrating entity: [domain.Employee#<null>]
DEBUG - binding '1981-01-05 11:27:05' to parameter: 1
DEBUG - binding 'Veenendaal' to parameter: 2
DEBUG - binding 'Piet' to parameter: 3
DEBUG - binding 'Dorpsstraat 62' to parameter: 4
DEBUG - binding 'Vennema' to parameter: 5
DEBUG - binding 'NL' to parameter: 6
DEBUG - Natively generated identity: 2
DEBUG - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG - closing statement
DEBUG - Inserting entity: [domain.Employee#2]
DEBUG - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG - insert into Employee (department_name, id) values (?, ?)
Hibernate: insert into Employee (department_name, id) values (?, ?)
DEBUG - preparing statement
DEBUG - Dehydrating entity: [domain.Employee#2]
DEBUG - binding null to parameter: 1
DEBUG - binding '2' to parameter: 2
DEBUG - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG - closing statement
DEBUG - could not insert: [domain.Employee] [insert into Employee (department_name, id) values (?, ?)]

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

Should I open a bug report for this?

emek · **Joined:** Wed Mar 08, 2006 9:36 am **Posts:** 4

I may be reaching here, but don't you need to specify an unsaved-value strategy besides id generation strategy in your class? Also, I think you may need a setter for the id, even if it is private.

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

Thank you for your thoughts

Well the set() and get() methods for the id and all the other fields are all there. (I left them out for improved reading claritiy)

I never heard of any unsaved value strategy before. I have looked it up with Google but it does not show much. Are you sure that that is a part of EJB3?

emmanuel · **Posted:** Sun Mar 12, 2006 4:50 pm

@ManyToOne(optional=false)

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

Hm,

I found out that something else is the problem, which seems to me like be a BUG.

Point is that after removing this line

Quote:

@Inheritance(strategy=InheritanceType.JOINED)

the problem is solved...

Emmanuel, can I get my credit back? ;-)

Nevertheless thanks for your time!

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

I don't know what exactly has happened but I cannot reproduce my own problem again.

Well, problem solved.

I think it was something like old database tables/constraints lying around. But that's just guessing since I have not been able to reproduce it.