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persistenceopenjpa

Single table inheritance insertion order

I have a following situation when I use OpenJPA:

Those 3 entities: SelectQueryElement, SingleSelectQueryElement, CompositeQueryElement are implemented thought SINGLE_TABLE inheritance.

I also have ColumnClass entity which holds top-level CompositeQueryElement. Each of these classes have EAGER loading and PERSIST/MERGE cascade type.

Class diagram

Now, if I want to mimic structure like this:

ColumnClass
|   CompositeSelectQueryElement // top-level query element
|   |   SingleSelectQueryElement 
|   |   CompositeSelectQueryElement 
|   |   |   SingleSelectQueryElement 
|   |   SingleSelectQueryElement
|   |   CompositeSelectQueryElement
|   |   |   SingleSelectQueryElement

... and I try to merge ColumnClass object, I expect for insertion order to be "preorder". But what I get not even close to that.

I expected the following insertion order:

   ColumnClass
1   |   CompositeSelectQueryElement // TOP-LEVEL
2   |   |   SingleSelectQueryElement
3   |   |   CompositeSelectQueryElement
4   |   |   |   SingleSelectQueryElement
5   |   |   SingleSelectQueryElement
6   |   |   CompositeSelectQueryElement
7   |   |   |   SingleSelectQueryElement

OR at least:

   ColumnClass
1   |   CompositeSelectQueryElement // TOP-LEVEL
2   |   |   SingleSelectQueryElement
3   |   |   CompositeSelectQueryElement
6   |   |   |   SingleSelectQueryElement
4   |   |   SingleSelectQueryElement
5   |   |   CompositeSelectQueryElement
7   |   |   |   SingleSelectQueryElement

But what I got was this: (note that first come all Composites and after them all Singles)

   ColumnClass
1   |   CompositeSelectQueryElement // TOP-LEVEL
4   |   |   SingleSelectQueryElement
2   |   |   CompositeSelectQueryElement
5   |   |   |   SingleSelectQueryElement
6   |   |   SingleSelectQueryElement
3   |   |   CompositeSelectQueryElement
7   |   |   |   SingleSelectQueryElement

Order of Singles is not consistent either. Sometimes it's nothing like this but all random.

The question: is there any way to work around this ordering issue and "suggest" to OpenJPA what I want to achieve.

I use OpenJPA v2.2.

Solution

  • This message from the OpenJPA mailing list seems to suggest your solution is to include <property name="openjpa.jdbc.UpdateManager" value="operation-order"> in your configuration. Hope that helps.