Home » Modeling » EMF » [CDO] Reference to CDOObject
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| Re: [CDO] Reference to CDOObject [message #882278 is a reply to message #882052] |
Wed, 06 June 2012 07:21   |
 Christophe MOINE
Messages: 34
Registered: February 2012 |
Member |
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> Am 05.06.2012 19:32, schrieb Christophe MOINE:
> > Hello CDO Team,
> >
> > I would like to make a reference to a CDOObject in my model;
> Why not just througha normal EReference?
an EReference of which kind ? I cannot choose EObject or something like that 
> > for now I did the trick with a long Attribute that stores the CDO IDs, but it enforces me the make several
> > transactions to get a valid CDO ID...
> Yes, that's a known problem with store-assigned IDs.
Ok no problem...
> > The only remaining way left I see is to make a SuperType for everyone of my classes, but that is a bit tedious:
> What do you mean by super type? How's that supposed to work?
I maybe should say super interface, such as an EClass "ModelElement": each EClass should implement this super interface. Then I would make a reference of type "ModelElement".
> > do you see any other ways ?
> With CDO 4.1 you can use client-assigned IDs. Please refer to
> 352561: Support client assigned CDOIDs (UUIDs)
If I understand well, it uses UUIDs, which sounds really nice... Is there some performance difference when using UUIDs since the server doesn't need to calculate the next suitable cdoID ?
> Another way would be to implement a mechanism that allows the server to modify a committed changeset before it reaches
the storage layer.
Sounds a bit complicated for me 
Cheers,
Christophe.
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| Re: [CDO] Reference to CDOObject [message #882294 is a reply to message #882278] |
Wed, 06 June 2012 07:41 |
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Am 06.06.2012 09:21, schrieb Christophe MOINE:
>> Am 05.06.2012 19:32, schrieb Christophe MOINE:
>> > Hello CDO Team,
>> >
>> > I would like to make a reference to a CDOObject in my model; Why not just througha normal EReference?
>
> an EReference of which kind ? I cannot choose EObject or something like that :(
Oh, why not?
>
>> > for now I did the trick with a long Attribute that stores the CDO IDs, but it enforces me the make several >
>> transactions to get a valid CDO ID...
>> Yes, that's a known problem with store-assigned IDs.
> Ok no problem...
>
>> > :( The only remaining way left I see is to make a SuperType for everyone of my classes, but that is a bit tedious:
>> What do you mean by super type? How's that supposed to work?
>
> I maybe should say super interface, such as an EClass "ModelElement": each EClass should implement this super
> interface. Then I would make a reference of type "ModelElement".
Now I see what you mean. I think EObject should work, too.
>
>> > do you see any other ways ?
>> With CDO 4.1 you can use client-assigned IDs. Please refer to
>> 352561: Support client assigned CDOIDs (UUIDs)
>
> If I understand well, it uses UUIDs, which sounds really nice... Is there some performance difference when using UUIDs
> since the server doesn't need to calculate the next suitable cdoID ?
I can just guess that the opposite is the case: String IDs consume more space in memory and in the DB. Processing them
here and there would probably also consume some extra cycles.
>
>
>> Another way would be to implement a mechanism that allows the server to modify a committed changeset before it reaches
> the storage layer.
>
> Sounds a bit complicated for me :)
Certainly quicker if I'd do it :P
Cheers
/Eike
----
http://www.esc-net.de
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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