----- Original Message -----
From: "Ralph Jensen" <[EMAIL PROTECTED]>
> For the moment I will try this:
>
> In the sql-script:
>
> create table uniqueInteger(
> pk INTEGER constraint pk_unique primary key,
> uniqueID INTEGER
> );
>
> insert into uniqueInteger VALUES( 1, 1 );
>
>
> Then in the bean:
> SELECT uniqueID from uniqeInteger;
>
> save uniqueID in variable ( let's call it 'uniqueVar' )
>
> then:
>
> UPDATE uniqueInteger SET uniqueID = uniqueVar+1 WHERE pk = 1;
>
>
> I think that's basically Vinay's suggestion. Does that look reasonable?
Nope. It doesn't handle concurrent access. Anytime you separate your read from
your update you are open to concurrency issues. If you are going to take this
route, you will have to obtain a table lock...which is going to be db specific.
There is much discussion on this topic in most SQL books, and also on
theserverside.com are a few threads.
jim
>
> ----- Original Message -----
> From: Jim Downing <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, May 04, 2001 5:47 PM
> Subject: Re: [JBoss-user] EJB question
>
>
> > Check out www.activescript.co.uk for a non-free ($99) component to
> generate
> > unique ids. The author has also posted the pattern on theserverside.com,
> so
> > you have something to work to if you want to implement it yourself.
> >
> > jim
> >
> > ----- Original Message -----
> > From: "Ralph Jensen" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Friday, May 04, 2001 10:25 AM
> > Subject: Re: [JBoss-user] EJB question
> >
> >
> > > The portability would be there in terms of data access. How to tell the
> > > database to autoincrement when I create a table is probably always
> > database
> > > specific. Or not?
> > >
> > > I'm not good at SQL. So how would your suggestion look in code? What
> would
> > > the key generator bean look like? Off which table would it work?
> > >
> > > Ralph
> > >
> > > ----- Original Message -----
> > > From: Vinay Menon <[EMAIL PROTECTED]>
> > > To: JBOSS <[EMAIL PROTECTED]>
> > > Sent: Friday, May 04, 2001 4:29 PM
> > > Subject: Re: [JBoss-user] EJB question
> > >
> > >
> > > Why don't you just use a primary key generator bean to encapsulate the
> key
> > > genaration? The ejbCreate can then work off that ejb and assign the
> > primary
> > > key field to the primary key generated field? so your autoincrement
> > > essentially will not be on the same table as the ejb but a different
> one
> > > and the primary key generator will work off that table. [Also makes
> sure
> > > that you have complete protability in terms of the database server!]
> > >
> > > Vinay
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: Ralph Jensen
> > > Sent: Friday, May 04, 2001 8:52 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: [JBoss-user] EJB question
> > >
> > >
> > > I asked this question elsewhere, but didn't get an answer. So:
> > >
> > > An entity bean's ejbCreate(...) method MUST return the primary key.
> That
> > is
> > > not a problem, if I specify the primary key myself and pass it to the
> > > create(...) method.
> > >
> > > But I want to let the database assign the primary key by creating a
> table
> > > with an AUTOINCREMENT default for the primary key column, like in this
> > > example using Cloudscape (part of SUN's J2EE v1.3):
> > >
> > > create table myTable(
> > > id INT DEFAULT AUTOINCREMENT CONSTRAINT pk_id PRIMARY KEY,
> > > someString VARCHAR(6),
> > > etc.
> > > );
> > >
> > > Then I can use INSERT like this:
> > > INSERT INTO mytable ( someString ) VALUES ( 'Hello' );
> > >
> > > The database then assigns a unique value to the id column of that new
> > > record.
> > >
> > > If I do this in the ejbCreate(...) method of my bean my problem is: How
> do
> > > I know that value in order to return it? Is that possible?
> > >
> > > Thanks
> > >
> > > Ralph Jensen
> > >
> > >
> > > _______________________________________________
> > > JBoss-user mailing list
> > > [EMAIL PROTECTED]
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> > clear=all><hr>Get
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> > > href="http://explorer.msn.com";>http://explorer.msn.com</a><br></p>
> > >
> > >
> > >
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