Subject Re: [ib-support] Sequential running no using trigger and generator
Author junior
Hi Svein!

Thanks for your alternative, it's definitely much better crafted than my
quick (and may be unreliable) solution.

Best wishes,
jr

----- Original Message -----
From: "Svein Erling Tysvær" <svein.erling.tysvaer@...>
To: <ib-support@yahoogroups.com>
Sent: Thursday, August 16, 2001 4:34 PM
Subject: Re: [ib-support] Sequential running no using trigger and generator


> Hi Junior!
>
> >Which way is better, any unwanted side effects? Or is there better ideas?
>
> Don't know if my suggestion is any better, but it is at least different:
>
> First of all, do not make this sequential number your primary key (PK)!
Use
> a separate, normal generator to populate the PK. Then make a unique index
> on your sequential field. Get its value from a separate table (i.e. make
> one separate table with one PK field populated from a generator (this
field
> should have a descending index (or store the negative PK value)) and a
> field for current_sequential_value ) by something like SELECT
> current_sequential_value FROM my_sequential_table WHERE PK = (SELECT
> MAX(PK) FROM my_sequential_table), try to insert your record and post it
> with this value+1 in your sequential field. If it fails due to a violation
> of unique constraint on your sequential field, just increase the value
> until you succeed. Then insert a new record to my_sequential_table with
the
> current_sequential_value you chose that succeeded.
>
> HTH,
> Set
>
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