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From: Michael Peppler <mpeppler at MBAY dot NET>
Subject: Re: next key table
Date: Sep 18 1997 8:58PM

Doug Fairclough wrote:
> 
> http://www.sybase.com/products/whitepapers/pkey_wpaper.html
> 
> states that :
> 
> begin tran
> 
>     declare @next_key
>     update next_key set next_key = next_key + 1
>     select @next_key = next_key + 1 from next_key
> 
>     insert into data_table (key_column, ...) values (@next_key, ...)
> 
> commit tran
> 
> does anyone know if its necessary to have the 'insert' statement
> _within_ the transaction in order to gaurantee uniqueness in the
> keys generated ?

You should be fine.

In a previous life I had a stored proc that grabbed a key from
the key table, and the key was then used to insert a new row to another
table. I never wrapped the whole thing in a transaction as the only
thing that was important was getting a unique identifier, not
the order in which these identifiers were generated.

Michael
-- 
Michael Peppler       -||-  Data Migrations Inc.
mpeppler@datamig.com  -||-  http://www.mbay.net/~mpeppler