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| Re: CDO DBStore with existing Hibernate mapping [message #538815 is a reply to message #538775] |
Tue, 08 June 2010 17:12   |
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Hi Eric,
The IStores that we provide differ in terms of
a) supported CDO functionality (auditing, branching, partial collection
loading, etc)
b) CDO-Specific requirements for the back-end schema (how much/little
has to be changed)
In contrast to the DBStore the Teneo-based HibernateStore is currently
supporting a reduced set of CDO functionality but is way more flexible
to map models to legacy schemas. I still think there are some changes
necessary, but maybe it's limited to the addition of system tables (i.e.
no changes to existing tables). Martin, can you clarify this for us?
As you mentioned there's a third option. You could implement your own
IStore and do what you need to do. As a starter there's some information
in
http://www.eclipse.org/cdo/documentation/manual_20.php?topic =extenders/developing_custom_stores
.. And this forum contains a few threads, too.
Cheers
/Eike
----
http://thegordian.blogspot.com
http://twitter.com/eikestepper
Am 08.06.2010 17:30, schrieb eric.lindahl@gmail.com:
> I already have an existing graph oriented EAV schema implemented using
> Hibernate.
> I would like to use CDO but I am unsure how and where the mapping
> should occur.
> Should I implement a custom DBStore and skip Teneo?
> Should I customize the mappings with Teneo?
> Should I skip Hibernate and use JBDC directly?
>
> My feeling is that Hibernate is not efficient at leveraging
> hierarchical queries to accelerate graph oriented queries.
>
> Thanks!
> Eric
>
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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| Re: CDO DBStore with existing Hibernate mapping [message #538825 is a reply to message #538815] |
Tue, 08 June 2010 17:45 |
 Martin Taal
Messages: 5468
Registered: July 2009 |
Senior Member |
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I don't have much to add. Indeed some extra system tables are needed. Two other limitations:
- currently the hibernate store does not support composite pk's
- the hibernate store needs a version number
For the rest you can map your legacy database using annotations in the model or in a separate xml file.
The hibernate store does not support an EAV mapping. This is supported by Teneo natively though:
http://wiki.eclipse.org/Teneo/Hibernate/ModelRelational/Enti ty_Attribute_Value_Mapping
But then you don't have any cdo functionality.
gr. Martin
Eike Stepper wrote:
> Hi Eric,
>
> The IStores that we provide differ in terms of
>
> a) supported CDO functionality (auditing, branching, partial collection
> loading, etc)
> b) CDO-Specific requirements for the back-end schema (how much/little
> has to be changed)
>
> In contrast to the DBStore the Teneo-based HibernateStore is currently
> supporting a reduced set of CDO functionality but is way more flexible
> to map models to legacy schemas. I still think there are some changes
> necessary, but maybe it's limited to the addition of system tables (i.e.
> no changes to existing tables). Martin, can you clarify this for us?
>
> As you mentioned there's a third option. You could implement your own
> IStore and do what you need to do. As a starter there's some information
> in
> http://www.eclipse.org/cdo/documentation/manual_20.php?topic =extenders/developing_custom_stores
> .. And this forum contains a few threads, too.
>
> Cheers
> /Eike
>
> ----
> http://thegordian.blogspot.com
> http://twitter.com/eikestepper
>
>
>
>
> Am 08.06.2010 17:30, schrieb eric.lindahl@gmail.com:
>> I already have an existing graph oriented EAV schema implemented using
>> Hibernate.
>> I would like to use CDO but I am unsure how and where the mapping
>> should occur.
>> Should I implement a custom DBStore and skip Teneo?
>> Should I customize the mappings with Teneo?
>> Should I skip Hibernate and use JBDC directly?
>>
>> My feeling is that Hibernate is not efficient at leveraging
>> hierarchical queries to accelerate graph oriented queries.
>>
>> Thanks!
>> Eric
>>
--
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@springsite.com - mtaal@elver.org
Web: www.springsite.com - www.elver.org
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| Re: CDO DBStore with existing Hibernate mapping [message #539726 is a reply to message #539052] |
Sat, 12 June 2010 09:00 |
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Hi Eric,
Comments below...
Am 09.06.2010 15:41, schrieb Eric Lindahl:
> Thanks for yoyr reply.
>
> I've not found an implementation of a custom StoreAccessor.
Hmm, what is "custom" and where did you look? CDO ships with four
different IStoreAccessor implementations.
> My approach is to implement a Store and use ObjectLong CDOID for
> hibernate swizzling.
If you want to use Hibernate why don't you use the shipped HibernateStore?
>
> This side of CDO I don't have much problem with, despite that
> implementing a simple Resource to do the same would have worked as well.
The total set of your requirements determines how simple a solution can
be and it seems still unclear to me what these requirement are.
>
> The UI side and all the events seem wrong headed to me.
What in particular? And I can't find "wrong headed" in my dictionary ;-(
> Why would I need anything other than the same Label Item providers
> that don't know the CDO namespace?
Why do you think you need something else?
> I do not think the CDO namespace need be anywhere but in specific IMPL
> of resources, editing domains, and command stacks.
Yes, that sounds like a good design. But note that not all CDO
functionality is made available through EMF APIs. Pessimistic locking is
one example.
> I already implement my own versions of these for logic interaction.
I'm not the UI expert but why do you need CDO-specific editing domains
and command stacks?
Cheers
/Eike
----
http://thegordian.blogspot.com
http://twitter.com/eikestepper
Cheers
/Eike
----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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