Using Toplink API to persist data to database

Question

My requirement is to persist data to the database (oracle) using Toplink Java API approach.
I have a basic setup program, but its not solving the purpose.
Kindly let me know where I am missing.
package sample;
import oracle.toplink.essentials.descriptors.ClassDescriptor;
import oracle.toplink.essentials.descriptors.RelationalDescriptor;
import oracle.toplink.essentials.internal.sessions.DatabaseSessionImpl;
import oracle.toplink.essentials.mappings.DirectToFieldMapping;
import oracle.toplink.essentials.queryframework.DatabaseQuery;
import oracle.toplink.essentials.sessions.Login;
import oracle.toplink.essentials.sessions.UnitOfWork;
public class EmployeeProject extends oracle.toplink.essentials.sessions.Project
private ClassDescriptor classDescriptor;
public EmployeeProject()
applyPROJECT();
applyLOGIN();
classDescriptor = buildEmployeeDescriptor();
addDescriptor(classDescriptor);
System.out.println("classDescriptor.getMappings(): " + classDescriptor.getMappings());
protected void applyPROJECT(){
setName("Employee");
protected void applyLOGIN()
oracle.toplink.essentials.sessions.DatabaseLogin login = new oracle.toplink.essentials.sessions.DatabaseLogin();
login.setDriverClassName("oracle.jdbc.OracleDriver");
login.setConnectionString("jdbc:oracle:thin:ptyagi-pc.idc.oracle.com:1521:orcl");
login.setUserName("system");
login.setPassword("orcl");
// Configuration Properties
setDatasourceLogin((Login)login);
// SECTION: DESCRIPTOR
public ClassDescriptor buildEmployeeDescriptor() {
RelationalDescriptor descriptor = new RelationalDescriptor();
// specify the class to be made persistent
descriptor.setJavaClass(sample.Employee.class);
// specify the tables to be used and primary key
descriptor.addTableName("EMP1");
descriptor.addPrimaryKeyFieldName("EMP1.ID");
// Descriptor Properties
descriptor.useSoftCacheWeakIdentityMap();
descriptor.setIdentityMapSize(100);
descriptor.setAlias("Employee");
// Mappings
DirectToFieldMapping idMapping = new DirectToFieldMapping();
idMapping.setAttributeName("id");
idMapping.setFieldName("EMP1.ID");
descriptor.addMapping(idMapping);
DirectToFieldMapping nameMapping = new DirectToFieldMapping();
nameMapping.setAttributeName("name");
nameMapping.setFieldName("EMP1.NAME");
descriptor.addMapping(nameMapping);
DirectToFieldMapping salMapping = new DirectToFieldMapping();
salMapping.setAttributeName("salary");
salMapping.setFieldName("EMP1.SALARY");
descriptor.addMapping(salMapping);
return descriptor;
public static void main(String [] args) {
EmployeeProject empProj = new EmployeeProject();
Employee emp = new Employee();
emp.setID(1);
emp.setName("Pulkita");
emp.setSalary(100);
DatabaseSessionImpl databaseSessionImpl = new DatabaseSessionImpl(empProj);
databaseSessionImpl.login();
databaseSessionImpl.beginTransaction();
UnitOfWork unitOfWork = databaseSessionImpl.acquireUnitOfWork();
unitOfWork.registerNewObject(emp);
unitOfWork.commit();
}

Answer 1

The issue is with the line:
databaseSessionImpl.beginTransaction();Since you began the transaction yourself you must also commit it. The easiest solution is to remove the above line and allow the UnitOfWork to begin and commit the transaction itself.
Doug