cayenne-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Andrus Adamchik <and...@objectstyle.org>
Subject Re: Reordering of database operations causes violation of unique constraint
Date Thu, 12 May 2016 14:12:34 GMT
Re-reading CAY-1898, it is about unique constraints, not FK constraints. So this is not about
cycles, and my explanation does not apply :) The first workaround applies though (which is
the same as what Ari had suggested in the original reply: https://lists.apache.org/thread.html/Z8c9iuyg8obghec
)

Andrus


> On May 12, 2016, at 7:08 AM, Andrus Adamchik <andrus@objectstyle.org> wrote:
> 
> Hi Andrea,
> 
> We saw your message to dev@ already, and there was a reply:
> 
> https://lists.apache.org/thread.html/Z8c9iuyg8obghec
> 
> I guess you haven't seen it as the reply was sent to the list, not to you directly. So
now I am including your address in cc:. 
> 
> Now back to your question. Cayenne does operation ordering to satisfy the constraints.
But the graph sort algorithm has a few known limitations. Namely it doesn't know how to order
dependency cycles (e.g. Employee -> Department -> Manager, who is also an employee).
Those have to be resoled manually. There are two solutions:
> 
> * Manual two-step commits - helps to resolve real cycles, when there's no valid ordering
satisfying the constraints at all.
> * @SortWeight annotation, which forces a certain predefined commit order between two
or more entities. It helps to resolve cases with "virtual" cycles (where Cayenne thinks there's
a cycle, but the actual commit still has a valid operation ordering that satisfies constraints).
> 
> Andrus
> 
>> On May 12, 2016, at 1:15 AM, Andrea Biasillo <ab@dataloy.com> wrote:
>> 
>> Hi!
>> 
>> My name is Andrea Biasillo, I am software architect in Dataloy AS, Bergen
>> Norway. In one of our project we use Cayenne as ORM. Unfortunately we are
>> facing the same problem reported by this case:
>> 
>> https://issues.apache.org/jira/browse/CAY-1898
>> 
>> Is  this case never  been taken in consideration? Is there a solution or at
>> least a work-wround?
>> 
>> Many regards
>> 
>> -- 
>> 
>> Andrea Biasillo - Dataloy Systems
>> 
>> P: +47 55 36 03 00
>> 
>> M: +4746542580 <%2B47%2055%2036%2003%2000>
>> 
>> Dataloy Service Desk <http://support.dataloy.com/>
>> 
>> Dataloy Knowledge Base <http://kb.dataloy.com/>
>> 
>> Subscribe to the Dataloy Newsletter <http://dataloy-systems.com/?page_id=591>
>> 
>> twitter.com/dataloy
>> 
>> www.dataloy-systems.com
> 


Mime
View raw message