users@jpa-spec.java.net

[jpa-spec users] Re: JPA support for recursive data structures / object graphs

From: Paul Benedict <pbenedict_at_apache.org>
Date: Tue, 26 Jan 2016 10:51:40 -0600

Christian, I am only aware of Oracle using CONNECT BY. Are there other
database vendors that support this? If it's only one vendor, I am not sure
a general JPA solution is appropriate; but that's going to be based on your
researched answer.

Cheers,
Paul

On Tue, Jan 26, 2016 at 10:45 AM, Christian Beikov <
christian.beikov_at_gmail.com> wrote:

> No I didn't mention this to the JPA spec lead yet. I wanted to create a
> POC first and get feedback from the Hibernate team before actually
> discussing standardization within JPA.
> As you already mentioned, there are many RDBMS vendors that simply don't
> or just partially support CTEs. At the moment the library fails with an
> exception if a feature that you use isn't supported by the RDBMS.
>
> I don't have full EclipseLink support yet but I'd be happy to implement it
> with some help.
>
> Regards,
> Christian
>
> Am 26.01.2016 um 13:34 schrieb Heiko Wagner:
>
> Hello Christian,
>
> thanks for your reply. Glad to hear that I am not the only one with this
> problem. Did you already approach the JPA spec lead/team, what they think
> about adding CTE query support to JPAQL? I know that current RDBMS support
> for CTEs strongly varies among the different vendors, which makes
> implementing a proper portable abstraction a real pain.
>
> I will take a closer look at your project soon. I am currently using
> EclipseLink. From the quick look at the github page, I am assuming there is
> also support for EclipseLink?
>
> Regards,
>
> Heiko
>
> Am 2016-01-26 12:36, schrieb Christian Beikov:
>
> Hello,
>
> I had the same problem as you did, missing support for CTEs.
> That's one reason why I created blaze-persistence[1 <https://github.com/Blazebit/blaze-persistence>] which implements support for CTEs for Hibernate.
>
> Hope this library can help you to ease your pain in the meantime until JPA gets these features.
>
> Regards,
> Christian
>
> [1] https://github.com/Blazebit/blaze-persistence
>
> Am 26.01.2016 um 10:33 schrieb heiko.wagner_at_apis.de:
>
> Hi, I am currently working on a proof of concept Java SE application. I am
> using JPA for persintence, since I am faliliar with it from my Java EE
> project. I am trying to find out what would be a good solution to store
> directed acyclic object graphs. As far as I found out, there is no
> abstraction support for "CONNECT BY" / recursive CTEs in JPA. I could
> resort back to using native queries or drop JPA entirely in favour of a
> graph oriented db. Are there any condierations of providing support in JPA
> for this in the future?
>
>
>