> well in general it works... there were some calculations before using the parent instance, > but somewhen it stops because of a NullPointerException. > it looks like a data container ran into an overflow, threw away some > database objects and didn't reload > them as they were accessed. as i wrote before: when i load them, > everything is well referenced.
It is difficult for me to comment without understanding the problem further. > if you think, using <inheritance> and <discriminator...> could help in > that way, JPA will call your intent of storing each derived type from a common base type to separate tables as TABLE_PER_CLASS strategy. As that is not the default strategy for inheritance mapping, there should be a <inheritance> specification within the <entity>. <discriminator> is not relevant because you are not using SINGLE_TABLE strategy where each record type must be discriminated from other type stored in the same table. > can you give an example, where i need to put this <inheritance> and > <discriminator...> stuff? > can you please make an example for the superclass and one derived class? I can, but it will take a while as I am in the middle of something else. Please browse OpenJPA test source codes -- it has examples of such inheritance mapping with @MappedSuperclass. > its openJPA 1.2.2 by the way... That can be a reason -- remember fixing a significant error in MappedSuperclass post 1.2.2 -- if possible try to switch to a 2.0 version to check if things improve. ----- Pinaki -- View this message in context: http://openjpa.208410.n2.nabble.com/Parent-reference-is-loaded-but-disappears-while-working-with-the-object-tp5728025p5744493.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
