Thank you afryer for that helfpul explanation. The User is and will never referenced by an other table. Therefore the database allows changing username/primary key. I am not allowed to change the tables, so I can't add an Id attribute for instance.
I didn't know that the EntityManager caches entities by primary key. Changing the key would surely cause problems. So I solved my problem deleting the user and adding the user again with new values. Thank you for your help. -- View this message in context: http://openjpa.208410.n2.nabble.com/Change-value-of-primary-key-field-tp7580285p7580301.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
