Sorry, it was not meant that the Unique ID is a DB concept but
that for regular DBs the Primary Key (and we are here speaking
from a "artifical key") is a unique number.
I agree that there are other persistent stores which also use
a unique ID. But normally you use one persistent store and
I think then you should use their ID generator (if available)
not only the one from the particular DB.
The database ID generator only guarantes that it delivers a
unique ID on a request as long as the generator is not tampered.
But when you generate the unique ID in an EJB the generation is
hidden from the DB and you have to know the state of this EJB
to understand how the IDs are generated in the DB. Especially when
you change data on a DB level you must change the EJB which is
not that easy (especially for a DBA).
Have fun - Andy
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, April 11, 2001 8:37 AM
> To: [EMAIL PROTECTED]
> Subject: RE: [JBoss-dev] Object Unique Id Generator
>
>
> The unique id is not a db concept. The application should have the
> flexibility to use multiple persistent stores such as
> directory servers,
> message queues, files, etc. The id should not be dependent on any one
> persistent store for generating id's because it binds the
> other persistent
> storages to that particular persistent store, the
> application itself should
> provide id's to reduce coupling between the components of the
> system. What
> is the benefit of having the id generation inside the
> database? At best, the
> database can only guarantee database scope uniqueness.
>
>
> Scott
>
> -----Original Message-----
> From: Jay Walters [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, April 11, 2001 9:29 AM
> To: ''[EMAIL PROTECTED]' '
> Subject: RE: [JBoss-dev] Object Unique Id Generator
>
>
> I think one of the issues here is what type of development is
> being done.
> If it's for internal use, generally you're already wedded to
> a database
> product and it's unlikely you'll change due to operational
> considerations.
> If you're building a product which needs to run with multiple
> databases then
> you need to address database portability issues.
>
> Cheers
> Jay
>
> -----Original Message-----
> From: Schaefer, Andreas
> To: '[EMAIL PROTECTED]'
> Sent: 4/10/01 2:32 PM
> Subject: RE: [JBoss-dev] Object Unique Id Generator
>
> There is a conceptual issue I like to raise here. From my
> point of view the "Unique Key" is part of the DB and therefore
> under the ownership of the DB. The idea I saw there would
> work under some assumptions:
> - DB belongs only to the application
> - There is no interaction with the DB except through the EJBs
> - DB is only the persistence tool
>
> If you want to add data to the DB through the DB directly
> like an import or through a backup.
>
> The Unique Key is a DB concept and therefore I think the
> key generation should remain within the DB.
>
> Have fun - Andy
>
> > -----Original Message-----
> > From: Sean Neville [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, April 10, 2001 11:01 AM
> > To: '[EMAIL PROTECTED]'
> > Subject: RE: [JBoss-dev] Object Unique Id Generator
> >
> >
> > There are a series of key generation patterns available on
> > The Server Side,
> > at least one of which requires no databases and no
> singletons, and is
> > therefore quite portable:
> >
> > http://www2.theserverside.com/patterns/index.jsp
> >
> >
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]]On Behalf Of
> > Schaefer, Andreas
> > Sent: Tuesday, April 10, 2001 1:22 PM
> > To: '[EMAIL PROTECTED]'
> > Subject: RE: [JBoss-dev] Object Unique Id Generator
> >
> >
> > Hi Geeks
> >
> > The "FOR UPDATE" is not always necessary as like in Oracle you
> > have a sequence generator delivering you an unique ID.
> >
> > For the other DBs it is maybe better to use a DB procedure or
> > function to generate an unique ID than use a SQL Statement.
> >
> > Have fun - Andy
> >
> > > -----Original Message-----
> > > From: Emmanuel Sciara [mailto:[EMAIL PROTECTED]]
> > > Sent: Tuesday, April 10, 2001 9:28 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: [JBoss-dev] Object Unique Id Generator
> > >
> > >
> > > Hi guys,
> > >
> > > I have written an advanced key generator for ejbs
> > > (http://ejbutils.sourceforge.net/). I would like to
> possibly have it
> > > blundled with JBoss. For this however, I need a database that
> > > supports "FOR
> > > UPDATE" sql clauses or transactions with serializable
> > isolation level.
> > >
> > > >From what I know, Hypersonic does not provide that and I
> > > moved away from
> > > InstantDB early in the process because I had problems with
> > > it, so I don't
> > > know.
> > >
> > > So I guess, my question is two fold:
> > > - Does JBoss have such database?
> > > - If yes, do you think it would be worth blundling this stuff
> > > with JBoss.
> > >
> > > Note: the source is a bit out of date on sourceforge but I am
> > > working on it.
> > > I have a fully JBoss-deployable version if you are interested.
> > >
> > > Emmanuel
> > >
> > > > From: "marc fleury" <[EMAIL PROTECTED]>
> > > > > post this to jboss-dev, I remember there is a key
> > > generator somewhere
> > > but
> > > > > yours might be more advanced. if you generate some
> > > interest there, you
> > > > are
> > > > > on
> > > > >
> > > > > marc
> > > > >
> > > > >
> > > > > |-----Original Message-----
> > > > > |From: Emmanuel Sciara [mailto:[EMAIL PROTECTED]]
> > > > > |Sent: Friday, April 06, 2001 10:31 AM
> > > > > |To: marc fleury
> > > > > |Subject: Re: Thanks
> > > > > |
> > > > > |
> > > > > |Hey!
> > > > > |
> > > > > |Cool Idea! I am interested for sure. Just tell me where
> > > to find the
> > > right
> > > > > |sample code and I am of! (if you can do that easily
> > > enough, that would
> > > > save
> > > > > |me some time)
> > > > > |
> > > > > |Just need to modify my sql so it does not use "For
> > > Update", which is
> > > not
> > > > > |supported by Hypersonic. I would like to write some doc
> > > too. But I
> > > guess
> > > > > |that can wait if I send some explanation mail to the list.
> > > > > |
> > > > > |Any other suggestion you would have?
> > > > > |
> > > > > |Emmanuel
> > > > > |
> > > > > |----- Original Message -----
> > > > > |From: "marc fleury" <[EMAIL PROTECTED]>
> > > > > |To: "Emmanuel Sciara" <[EMAIL PROTECTED]>
> > > > > |Sent: Thursday, April 05, 2001 6:28 PM
> > > > > |Subject: Thanks
> > > > > |
> > > > > |
> > > > > |> for removing the documentation from the website,
> > > > > |>
> > > > > |> also did you think about implementing the high/low
> > pattern and
> > > > > |putting it
> > > > > |> as an MBean (or Bean) in JBoss?
> > > > > |>
> > > > > |> let me know if interested let the list know and see if
> > > they want it.
> > > > > |>
> > > > > |> marc
> > > > > |>
> > > > > |>
> > > > > |> _________________
> > > > > |> Marc Fleury, Ph.D
> > > > > |> [EMAIL PROTECTED]
> > > > > |> _________________
> > > > > |
> > > >
> > > >
> > >
> > >
> > >
> > > _______________________________________________
> > > Jboss-development mailing list
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> > >
> >
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> >
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> >
>
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