Here are my answers to your questions:
1) I assume step 5 is a merge, so how are you holding onto E4 and does it have a primary key assigned after the transaction completes?
Yes step 5 is a merge. E4 is in a collection managed by the Company.
public class Company {
private List<Employee> employees;
…
}
2) How is the company obtained in the second transaction so that you can look up E4?
The client conveys to the server the E4’s ID (primary key).
The server uses that to do a entityManager.find(Employee.class, id_for_e4);
3) What is in the collection?
The employee entities. Or did I take your question too literally? Since using the debugger+break points did not help I resorted to the age old technique
of insert-a-print-statement. I listed the contents of the company.getEmployees() collection just before the failed deletion of E4. It only had E1 & E2.
4) How are you looking up E4 in the collection?
public void deleteEmployeeWithId(Long id) {
Employee e4 = entityManager.find(Employee.class, id);
List<Employee> employeesInCompany = e4.getCompany().getEmployees();
// Iterate over the employeesInCompany to find e4 and then remove it from the collection.
Sri
From: eclipselink-users-bounces@xxxxxxxxxxx [mailto:eclipselink-users-bounces@xxxxxxxxxxx]
On Behalf Of Christopher Delahunt
Sent: Friday, July 29, 2011 3:47 PM
To: EclipseLink User Discussions
Subject: Re: [eclipselink-users] Insertions missing
So steps 1-5 are one transaction context, and then are repeated in a second transaction.
Questions:
1) I assume step 5 is a merge, so how are you holding onto E4 and does it have a primary key assigned after the transaction completes?
2) How is the company obtained in the second transaction so that you can look up E4?
3) What is in the collection?
4) How are you looking up E4 in the collection?
Regards,
Chris
On 29/07/2011 3:08 PM, Sri Sankaran wrote:
I do not understand what you are referring to by “first transaction”. Here’s a little more detail on the implementation:
Precondition: Company has 3 Employees E1, E2, E3
User issues “delete E3” and “add E4” request
The server logic is implemented thusly:
Find Employee E3 in Company’s collection of Employees
Remove E3 from the collection – A pure Java operation, i.e. no dao.delete(employee)
dao.flush() – to ensure that the delete operation is executed. This is to work around Eclipselink’s desire to perform inserts
first (It is a longer sidebar to explain why we don’t want that to happen)
Add E4 to the Company’s collection of Employees
Save the Company to the database
Steps 1-5 are all a part of the same transaction.
The same steps repeat when user subsequently asks to delete E4 and add E5. It fails at step 2 saying that E4 does not exist.
Sri
Does the second step wait for the first transaction to commit before reading in the company? If not, you many need to refresh the company after the transaction is fully committed to see the changes as they are not visible to other contexts
until the commit occurs.
If this isn't the issue, can you describe the api you are using in each step?
Best Regards,
Chris
On 29/07/2011 12:41 PM, Sri Sankaran wrote:
Eclipselink version: 2.0.0
Consider the following simplification of my actual business case:
A Company entity has a collection of Employee entities
@Cache(shared = true, expiry = 900000)
@Table(name = "COMPANIES ")
@OneToMany(mappedBy = "company", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
public List<Employee> getEmployees() {
@Cache(shared = true, expiry = 900000)
@Table(name = "EMPLOYEES ")
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "COMPANY_ID", nullable = false)
Consider the case where a Company has 3 Employees (E1, E2 & E3).
The user of the application (using the user interface) deletes E3 & adds E4. The logic works correctly and E3 is removed from the database and an E4 is inserted.
Next, the user deletes E4 and adds E5. Now when application attempts to perform this operation, I am told that the employees collection that is owned by the Company object
does not contain an E4!!
How come? Recall that in the previous step the insert happened correctly. Equally puzzling – not to mention aggravating – is that if slowly step through the logic in a
debugger I do not see any error.
I should also mention an ominous warning I see when I build the application:
could not be weaved for change tracking as it is not supported by its mappings.
I have not figured its cause and I don’t know if this has any bearing on my current problem.
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