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From Donald McLean <dmclea...@gmail.com>
Subject Re: Problem with auto-generated identifiers
Date Thu, 09 Jul 2009 20:05:53 GMT
It seems that you would get that if you created a second object before
saving the first one. This could also happen if you had multiple
threads or multiple users accessing a server DB.

I would think that you would want to use "GENERATED ALWAYS AS
IDENTITY" for event_id rather than generating the key through
Hibernate.

On Thu, Jul 9, 2009 at 2:12 PM, Dimka<dmiperl@gmail.com> wrote:
>
> I am using embedded derby driver 10.4.2.0 - (689064)  with hibernate
> Every once in a while I'm seeing an exception like this:
>
> "The statement was aborted because it would have caused a duplicate key
> value in a unique or primary key constraint or unique index identified by
> 'SQL090709201522730' defined on 'MYTABLE' "
>
> I haven't seen such problems up until I've started to use auto-generated
> identifiers, like the one below:
>
> <id name="id" column="EVENT_ID" type="long">
>        <generator class="native">
>        </generator>
> </id>
>
> Fraction of the schema looks like this:
> CREATE TABLE MYTABLE(EVENT_ID BIGINT NOT NULL, .... PRIMARY KEY (EVENT_ID))
> CREATE TABLE hibernate_unique_key ( next_hi INTEGER )
> INSERT INTO  hibernate_unique_key VALUES ( 0 )
>
> The exception is thrown sometimes, not all the time.. I can't figure out why
> and when.
> This is the most frustrating thing.
> Can anyone give me a direction of where to look?
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