Re: Return key from query

On 2 November 2010 21:59, Rob Sargent <robjsargent(at)gmail(dot)com> wrote:

>
>
> On 11/02/2010 02:43 PM, Jonathan Tripathy wrote:
> > Hi everyone,
> >
> > When adding a new record, we run an insert query which auto-increments
> > the primary key for the table. However the method (in java) which calls
> > this query must return the newly created key.
> >
> > Any ideas on how to do this, preferably using a single transaction?
> >
> > Thanks
> >
>
> Ah yes have your cake and eat it too.
>
> If you app code (java) is making new instances and wants to have an id,
> then the table cannot have an auto-id.
>
>
why?

> I'm big on java/class id generation (usually use UUID) but you do have
> to take complete responsibility for it. The hibernate folks frown on it
> but their retort is imho woeful. If you're not using uuid's you will
> need a generator. You can back it up with a persistent store so you
> know where you left off, but you will want to (auto-)increment that id
> table with a large value (say 5000) and have you generate dole them out
> as needed at the app level. When it has spent 5000 ids, it will go to
> the server are ask for another 5000 (separate tx). Please don't get
> hung up on loosing some portion of the 5000 id when you restart or
> whatever.
>
>
I'm not fan of UUID, though I have to use it in many projects... nothing
special, just another id, not better, not worse than id, maybe except for
the chance of collisions :)

regards
Szymon