Re: [eclipselink-users] Unmanaged references

[mgsoft <mgsoft@xxxxxx>]

In our project we are working with data transfer objects. In boundary methods
a conversion from DTO to respective entity takes place.

public void updateCustomer(CustomerUpdateDTO dto) 
{
  // Find and attach customer entity
  Customer customer = crudService.findCustomerByCode(dto.getCode());

  customer.setName(dto.getName());
  // Rest omitted

  // The customer DTO references a list DTO for the customer's country
  // Of course the respective country entity exists in the database. 
  customer.setCountry(new Country(dto.getCountry().getCode()));
}

When flushing the entity manager tries to persist the "non-existing"
country. That's interesting because the association isn't annotated with a
cascade option! 
Anyway, the operation fails:
com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Column
'name' cannot be null
Error Code: 1048
Call: INSERT INTO country_tab (code, name) VALUES (?, ?)

The property "eclipselink.validate-existence" seems to work only when
persisting new objects.




James Sutherland wrote:
> 
> Although not generally a good idea, JPA does allow you to persist an
> object with a reference to a non-managed existing object.  Is the object
> existing?  What error do you get?
> 
> In general if you use merge() instead of persist() it should ensure the
> correct managed object is referenced.  You could also manually lookup the
> correct managed object to be referenced.
> 
> You could try the property "eclipselink.validate-existence", it may change
> the behavior.
> 
> 
> 
> mgsoft wrote:
>> 
>> Hi,
>> 
>> we are just in transition from Hibernate to EclipseLink. While running
>> the first tests we saw a difference between Hibernate and EclipseLink:
>> 
>> If I want to persist or update an entity that references an unmanaged
>> object I get an error message that tells me that persisting the
>> referenced unmanaged entity failed. Of course I don't want to cascade
>> e.g. the persist of the entity reference that even hasn't an apporpriate
>> annotation (Cascade.ALL or Cascade.Persist).
>> In Hibernate it works without a problem. Do I have to attach (e.g by
>> using find) the reference always before persisting an entity or is there
>> a global setting to change this behaviour?
>> 
>> Thanks in advance!
>> 
>> 
>> 
> 
> 

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