John, thanks for the reply...
Why do you feel I need a unique key generator? I want the userID to be the
key and I want it to be unique, and I want it to be user selected.
If the user selects an id thats in use, they can pick another and/or the
app can suggest one.
My primary concern is knowing if the user selected ID is already in use. Is
there a way I can use a unique key generator for that?
Thanks...
Jim
--On Friday, March 02, 2001 11:55 AM -0800 John Moore
<[EMAIL PROTECTED]> wrote:
>
>
> you need a unique key generator. Check out theserverside.com (patterns
> section) for discussion on ways to handle it. JBoss used to come with
> one but I don't see it any more.
>
>
> -----Original Message-----
> From: Jim Archer [mailto:[EMAIL PROTECTED]]
> Sent: Friday, March 02, 2001 11:45 AM
> To: JBoss-User
> Subject: [jBoss-User] Design question - Checking for an existing
> record??
>
> Hi All...
>
> I have what must be a fairly common problem and I was wondering if
> someone could suggest what they think the preferred solution might be.
>
> I need to create an EB for a user and I have set the userid up as a
> primary jey. Of course, the user ID must be unique. I'm wondering what
> the best way to detect that a new user has picked an unavailable user
> ID.
>
> First, I could just try to create the EB and catch a create exception.
> The downside to this seems to be that if I get a create exception I
> don't know for sure it was created sue to a non-unique key field without
> looking at the message text that might vary accross servers. So it seems
> that I can only know that there was some problem.
>
> The next option is to use the finder for primary key and see if I get a
> record back. This would answer the question but seems like extra overhead
> to introduce. Also, it would result in a FinderException when the userID
> is unique and I don't know if that will roll back the transaction I'm in
> or not. Of course, I have to check for existance and add the new one in
> the same transaction.
>
> Is there a third option? I would appreciate any suggestions!
>
> Thanks lots!
>
> Jim
>
> ********************************************
> I shall be telling this with a sigh
> Somewhere ages and ages hence:
> Two roads diverged in a wood, and I -
> I took the one less traveled by,
> And that has made all the difference.
>
> - Robert Frost, 1916
>
>
> --
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********************************************
I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I -
I took the one less traveled by,
And that has made all the difference.
- Robert Frost, 1916
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