While the character representation is less efficient, it is much more readable
for humans using SQL consoles or other non Hibernate layers.
On 28 mai 2010, at 21:23, Steve Ebersole wrote:
> I am pretty much done with the plumbing for this UUID support.
>
> However...
>
> Another difficulty is the standard database type to which to map UUIDs.
> BINARY(16) or CHAR(36) are the most common datatypes used that I have
> seen. I have also seen strategies using NUMERIC and two INTEGER values
> (splitting least/most significant bits); the later is not a viable
> option though for the built-in support.
>
> I have never used UUIDs as PK values so I am far from an expert here.
>> From my understanding the issue is that using the character
> representation not only wastes storage but also makes indexing and
> joining much slower. And do all databases support NUMERIC types large
> enough?
>
> Personally, I say we use BINARY(16) for the standard support. WDYT?
>
>
> On Thu, 2010-05-27 at 07:01 -0500, Steve Ebersole wrote:
>> Anyway, the discussion here wrt this UUID project is all about
>> generating the UUID value in Java. The first point is to determine
>> whether there is any benefit to relying on the database to generate
>> these for us in the cases when they can.
>>
>> Secondly there is the question of if we are going to do it in Java then
>> what is the correct approach. Both libraries mentioned here (UUID and
>> JUG) use MAC address resolution in building the uuid value. JUG is
>> updating to use java.util.UUID, but relies on native code for
>> mac-address-resoltion; UUID use its own UUID class but does not need
>> native code for the mac-address-resolution (it uses OS-sniffing and
>> system calls). Heck maybe we offer this as a strategy configurable with
>> the Configuration/SessionFactory.
>>
>> interface UUIDGenerationStrategy extends Serializable {
>> public int getGenerationVersion(); // informational
>> public UUID generateUUID(SessionImplementor session);
>> }
>>
>> But first things first...
>>
>> Do we use database uuid generation if supported? Is that itself perhaps
>> just a strategy?
>>
>>
>> On Thu, 2010-05-27 at 06:12 -0500, Steve Ebersole wrote:
>>> The site is not just about the UUID generator project. He wrote posts
>>> on ohter subjects as well.
>>>
>>> My point there is more to the maven repo. How do we reference this?
>>> Are we ending up hosting another artifact? How do we even contact
>>> him to find out?
>>>
>>>
>>>
>>>
>>>
>>> -- Sent from my Palm Pre
>>>
>>> st...@hibernate.org
>>> http://hibernate.org
>>> ______________________________________________________________________
>>> On May 27, 2010 1:28 AM, Emmanuel Bernard <emman...@hibernate.org>
>>> wrote:
>>>
>>> To his credit a UUID impl is not a 10 year project plan ;) I would not
>>> necessarily consider it abandonware rather than done.
>>>
>>> On 27 mai 2010, at 03:13, Steve Ebersole wrote:
>>>
>>>> and the latest posts on that website are
>>>> from 2007.
>>>
>>>
>>> _______________________________________________
>>> hibernate-dev mailing list
>>> hibernate-dev@lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>
>>
>
>
> --
> Steve Ebersole <st...@hibernate.org>
> http://hibernate.org
>
> _______________________________________________
> hibernate-dev mailing list
> hibernate-dev@lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hibernate-dev
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