How to persist an unmanaged property object

Posted on 2008-10-20
Medium Priority
Last Modified: 2013-11-24
I'm using an EJB 3.0 entity bean.

I want to save a new Employee entity bean and associate it to the department id = 44;

The way it works, I need to
1-fetch the department entity bean
2-Set the department into the employee
3-Save the employee.

If you notice, the first step is useless since I already know the Id of the department. Why should I fetch it and get a managed entity bean?

I would expect to be able to do that kind of save:

Department dep = new Department();

Employee emp = new Employee();


But that doesn't work because the framework forces to have a managed object as the department. I would have thought that when I set CascadeType to nothing it would do the trick but it doesnt.

Is there any workaround for this ?


Question by:kmapper
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2

Accepted Solution

Mr_It earned 2000 total points
ID: 22831262
If you don't already have or need the object, don't load it in memory. Obviously you don't need the Department object, so you are absolutely right that you don't want to load it.

Doesn't something like the code below work?
public void createEmployee(Employee emp, String departmentID) {
    emp.setDepartment(null); // If set to CascadeType.PERSIST, be sure NOT to have an unmanaged department in emp
    Query query = em.createQuery("UPDATE Employee e SET e.department.id = :depId WHERE e.id = :empId");
    query.setParameter("depId", departmentID);
    query.setParameter("empId", emp.getId());

Open in new window


Expert Comment

ID: 22842180
Thanks :-) I know it's still an INSERT and UPDATE statement, while it could be done in 1 INSERT statement if you use native SQL... This is just one disadvantage of using an ORM like JPA. It does not always do the most performant things.

Keep in mind that your managed Employee entity is not in sync anymore after such and UPDATE (or DELETE) statement. Maybe I should have put an em.clear() call as well after the flush.

Featured Post

Stack Overflow Podcast - Developer Story

Welcome to the Stack Overflow podcast recorded Thursday July 20 at Stack Overflow Headquearters in NYC. Your hosts today are podcast regulars Jay Hanlon, David Fullerton, and Ilana Yitzhaki, plus the quite irregular Matt Sherman (Stack Overflow Engineering Manager extraordinaire)

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I had a project requirement for a displaying a user workbench .This workbench would consist multiple data grids .In each grid the user will be able to see a large number of data. These data grids should allow the user to 1. Sort 2. Export the …
A solution for Fortify Path Manipulation.
The viewer will learn how to implement Singleton Design Pattern in Java.
This tutorial covers a practical example of lazy loading technique and early loading technique in a Singleton Design Pattern.
Suggested Courses
Course of the Month13 days, 21 hours left to enroll

800 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question