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
EmployeeCode:
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 (?, ?)]
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