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Getting a unique key to be used across tables
Message
From
28/10/2004 17:18:48
Charlie Schreiner
Myers and Stauffer Consulting
Topeka, Kansas, United States
 
 
General information
Forum:
Microsoft SQL Server
Category:
Stored procedures, Triggers, UDFs
Miscellaneous
Thread ID:
00955413
Message ID:
00955540
Views:
12
Hi Kevin,
Remember, I don't do SQL Server..., yet, but,
If you get the CurrTransNo and a TimeStamp, then you can update on that.
SELECT CurrTransNo, Stamp
Success
DO WHILE NOT Success
  UPDATE ... WHERE Stamp = StampIJustGot
  IF _TALLY or something like that > 0
    Success = .T.
  ELSE
    SELECT CurrTransNo, Stamp
  ENDIF
ENDDO
>We have a situation where we store a one column, one row entry called CurrTransNo. As the name implies, it stores the next transaction number to be used. This transaction number will be used across many different transaction tables, so it must be unique across all of the tables.
>
>We're trying to come up with the safest way to avoid any concurrency issues and to avoid any instance of duplicate transaction records. We have a stored procedure that increments the NextTransNo by one, and then returns the new number as a result, so it can be used, like so...
>
>
>
>DECLARE @nNextTransNo int
>
>UPDATE NextTransTable SET @nNextTransNo = CurrTransNo + 1, CurrTransNo = CurrTransNo + 1 FROM NextTransTable
>
>SELECT @nNextTransNo
>
>GO
>
>
>Short of implementing locks in SQL...since the setting of the variable and the updating of the record are done at what appears to be the same time - can anyone think of a better way to handle this?
>
>Thanks,
>Kevin
Charlie
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