Re: How to generate unique invoice numbers for each day - Mailing list pgsql-general

From Andy Colson
Subject Re: How to generate unique invoice numbers for each day
Date
Msg-id 4D331819.4080508@squeakycode.net
Whole thread Raw
In response to How to generate unique invoice numbers for each day  ("Andrus Moor" <kobruleht2@hot.ee>)
Responses Re: How to generate unique invoice numbers for each day  ("Andrus Moor" <kobruleht2@hot.ee>)
List pgsql-general
On 01/15/2011 12:13 PM, Andrus Moor wrote:
> Invoice numbers have format yymmddn
>
> where n is sequence number in day staring at 1 for every day.
>
> command
>
> SELECT COALESCE(MAX(nullif(substring( substring(tasudok from 7), '^[0-9]*'),'')::int),0)+1
> FROM invoice
> where date= ?invoicedate
>
> is used to get next free invoice number if new invoice is saved.
>
> If multiple invoices are saved concurrently from different processes, they will probably get same number.
>
> How to get unique invoice number for some day in 8.1+ when multiple users create new invoices ?
>
> Andrus.
>

I understand this is a business rule, and you cant change it.

My opinion is you are doing it wrong.  Don't encode more than one bit of data into one column.  You have two bits of
data,date and invoice number.  Use TWO columns!  Let the invoice number auto-inc and never reset it.  You want to find
invoiceson some day, query the date field.  You want to find a specific invoice, query the invoice number.  Dont
combinethe two.  Why write a bunch of bug ridden code that encodes and decodes the two fields into one? 

But I know... you cant change it.  Someone up the chain thinks its just the bee's knees.  I had to say it though.  Its
beensaid.  I will go in peace. 

-Andy

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