Hal, were you able to find the actual source for this? I searched and
searched last week with no luck...
Jim
--On Friday, May 04, 2001 8:33 AM -0400 "Deadman, Hal"
<[EMAIL PROTECTED]> wrote:
> Take a look at the key generator that comes with Exolab's Castor
> (open-source). http://castor.exolab.org/key-generator.html
>
> You probably want something like their HIGH/LOW generator. I haven't used
> it but I use a similiar technique that I wrote myself. I like their
> implementation better because they let you use different key gen
> techniques that you can specify in the config file without changing code.
> They offer a max+1 option which you should stay away from b/c I don't see
> how that could guarantee uniqueness.
>
> The castor high/low generator uses a database but it grabs a range of
> values with each db hit so you don't hit the db everytime.
>
> Hal
>
>> -----Original Message-----
>> From: Ralph Jensen [mailto:[EMAIL PROTECTED]]
>> Sent: Friday, May 04, 2001 7:27 AM
>> To: [EMAIL PROTECTED]
>> Subject: Re: [JBoss-user] EJB question
>>
>>
>> Thanks. But that is actually much more than I want. I only
>> need a unique
>> INT for primary keys.
>>
>> 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?
>> That's a lot of database access to get a unique primary key,
>> just to be
>> able to return it from ejbCreate() - especially in light of
>> the fact, that
>> databases do it automatically, if the table is created
>> accordingly. Isn't
>> this kind of thing done regularly?
>>
>>
>> I know this has nothing to do with jBoss. Thank you. :-)
>>
>> Ralph
>>
>> ----- 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
>> > >
>> > >
>> > > _______________________________________________
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>> > >
>> > >
>> > >
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And that has made all the difference.
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