Re: (SQL) Identity Crisis

[Charles Wilt <charles.wilt@xxxxxxxxx>]

I would hope that ALTER TABLE would work properly...though I've not really
tested it.

My experience with create table within the confines of an CMS showed the
problem.  I ended up creating a little utility that was invoked using an
exit point in the CMS that would determine the highest current value of the
identity column and issue an ALTER TABLE ALTER COLUMN myID RESTART WITH
:MaxNbr + 1.

Also not that the GENERATED ALWAYS might be problematic when recreating the
table...as I believe unless you've never deleted anything from the table
and the system reads the original data in identity order, you'll find that
your identity columns get new values when the data is copied back.

Charles


On Fri, Apr 5, 2013 at 1:33 PM, Anderson, Kurt <KAnderson@xxxxxxxxxxxx>wrote:

> Well, crisis somewhat averted, but I'm having an issue with an identity
> field in a SQL created file.
>
> Here's an excerpt from the table definition:
>    EditID     Dec            (10, 0)      NOT NULL GENERATED ALWAYS AS
> IDENTITY
>                                         (START WITH 1 INCREMENT BY 1
> CYCLE),
>    Primary Key(EditID)
>
> The file was created last October and has been fine all along.   Today we
> added a new field to the file and recreated the table.  We copied the old
> records in, and they retained their EditID values, so that was great.
>  However, the moment a record was added, it attempted to start at 1 again
> and got a duplicate record error.   Crap!   To get around the issue, for
> the time being, I modified the EditID definition to "START WITH 8060."
>  We're off and running again.
>
> For every change to the file will the "START WITH" have to be modified?
> Is there another way to get around this issue?
>
> I have a feeling the answer might be to use ALTER TABLE instead of
> recreating the file.  It's not that I'm against that, it's just that I'm
> already introducing a lot of change (new stuff) here, and I don't want that
> bubble to burst.   In addition, we don't have change management software
> (sigh), so I ended up creating a system to implement files across all of
> our clients' libraries. To have to redesign it to know if the RUNSQLSTM it
> runs is executing a CREATE or an ALTER is a big deal.
>
> I appreciate any input.
>
> We're on IBM i 7.1.
>
> Thanks,
> Kurt Anderson
> Sr. Programmer/Analyst
> CustomCall Data Systems, a division of Enghouse Systems Ltd.
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