Re: getting duplicate number is there a - Mailing list pgsql-sql

Joel Fradkin wrote:
> I was using SET TRANSACTION ISOLATION LEVEL SERIALIZABLE in MSSQL.
> 
> Is there something similar in postgres to ensure its not in the middle of
> being updated?

Yep - see the SQL COMMANDS reference section under SET TRANSACTION ...
You could use LOCK TABLE too.
See Chapter 12 - Concurrency Control for discussion.

>             sql = "SELECT COUNT(*) FROM tblcase WHERE LocationID = " &
> intLocationID & _
>                   " and substr(casenum,length(casenum)-1,2) = '" &
> right(year(date),2) & "' AND clientnum = '" & _
> 
>                   chrClientNum & "'"
> 
> I will add a select just before doing the insert to see if this helps, its
> not happening a bunch, but 5 6 times a day is still an issue for me.
> 
> I use the count as a segment of my case number so each time a new case is
> entered the count goes up for that location for that year.

I'd be tempted to have a case_numbers table with (year,location,max_num) 
and lock/read/insert to that. Makes everything explicit, and means you 
don't have to mess around with counts/substrings.

--  Richard Huxton  Archonet Ltd