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Using EObjectStore to select column values [message #1064636]

Thu, 20 June 2013 11:08

Kacper Zając

Messages: 2
Registered: June 2013

Junior Member

Hello,
I have created model (domain and persistence classes) using Texo / ecore and I am using
EObjectStore.query to make database queries. For queries which result is collection
of ecore model classes it works fine.
Problem occurs, when I want to select something different. F.e. specific values from single column or use aggregate functions.
For query:
select sum(e.workingHours) from timesheet_TimeSheetEntry as e
I am getting exception like:

java.lang.IllegalStateException: The class class java.lang.Long is not managed by this ModelResolver

Class may vary - it depends on select statement. You can get same exception with java.lang.String or java.lang.Integer

Could you advise me what should I do to get this type of queries working ?

Cheers,
Kacper

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Re: Using EObjectStore to select column values [message #1065045 is a reply to message #1064636]

Mon, 24 June 2013 04:34

Martin Taal

Messages: 5468
Registered: July 2009

Senior Member

Hi Kacper,
Sorry for the later reply.. The EObjectStore has an api which returns EObjects. I think the best solution for you is to
use the EntityManagerFactory (for example from the EntityManagerProvider) directly to get an EntityManager and from then
on query in the standard JPA way.

Or are you using a JSONEObjectStore?

gr. Martin

On 06/20/2013 02:45 PM, Kacper Zając wrote:
> Hello,
> I have created model (domain and persistence classes) using Texo / ecore and I am using
> EObjectStore.query to make database queries. For queries which result is collection of ecore model classes it works fine.
> Problem occurs, when I want to select something different. F.e. specific values from single column or use aggregate
> functions.
> For query:
> select sum(e.workingHours) from timesheet_TimeSheetEntry as e
> I am getting exception like:
>
> java.lang.IllegalStateException: The class class java.lang.Long is not managed by this ModelResolver
>
> Class may vary - it depends on select statement. You can get same exception with java.lang.String or java.lang.Integer
>
> Could you advise me what should I do to get this type of queries working ?
>
> Cheers,
> Kacper

--

With Regards, Martin Taal

Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Cell: +31 (0)6 288 48 943
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@xxxxxxxx - mtaal@xxxxxxxx
Web: www.springsite.com - www.elver.org

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Re: Using EObjectStore to select column values [message #1065170 is a reply to message #1065045]

Mon, 24 June 2013 14:57

Kacper Zając

Messages: 2
Registered: June 2013

Junior Member

Hi Martin,
Thanks for your reply and clarifying situation. That's the solution I was afraid of.
I have seen that there's implemented functionality for count queries using EObjectStore, and I hoped,
that I won't have to mix EntityManager code with EObjectStore in services.

Actual EObjectStore, which I am using is EPersistenceService, so it's not JSONEObjectStore.

regards,
Kacper

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Re: Using EObjectStore to select column values [message #1065174 is a reply to message #1065170]

Mon, 24 June 2013 15:13

Martin Taal

Messages: 5468
Registered: July 2009

Senior Member

Hi Kacper,
Yes I can see the requirement, but I am bit in doubt on how to add this in a nice way while still following the idea
that an EObjectStore actually stores and retrieves EObjects.
So I can add a free format query api/method to EObjectStore to return such free-results. Or add a new eobject type in
Texo which has an array/list of objects as an efeature to store the data in there and return then a list of these
EObject instances.

Can you enter a bugzilla for this? (with a link to this forum discussion)
Maybe I can solve it somewhat nicely while still following the api/EObjectStore concept.

gr. Martin

On 06/24/2013 04:57 PM, Kacper Zając wrote:
> Hi Martin,
> Thanks for your reply and clarifying situation. That's the solution I was afraid of. I have seen that there's
> implemented functionality for count queries using EObjectStore, and I hoped,
> that I won't have to mix EntityManager code with EObjectStore in services.
>
> Actual EObjectStore, which I am using is EPersistenceService, so it's not JSONEObjectStore.
>
> regards,
> Kacper

--

With Regards, Martin Taal

Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Cell: +31 (0)6 288 48 943
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@xxxxxxxx - mtaal@xxxxxxxx
Web: www.springsite.com - www.elver.org

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