Subject Re: Invoice number
From Akshat Kapoor <akshat.kapoor@kapoorsons.in>
Date Sun, 6 Sep 2020 21:23:01 +0530
Newsgroups dbase.getting-started

On 06.09.2020 04:59, Bami Onwu wrote:
> Hi all,
 >
> I created invoicing app for a customer and it's working fine on standalone. When working under multiuser, it assigns one invoice number to two users.
 >
> The invoice numbering is no more unique. I need advice on how to go about this.
Good Evening Bami,
We do not have any info as to when and how new invoice numbers are being
generated. So cannot say for sure but I agree with Ken that do not
generate invoice numbers before hand. Generate them at the last moment
before actual saving of row.

I have been using this system for the past 15+ years and never had any
issue.

Before that I also used to face this issue but ever since this system
has been implemented never faced this issue.

Some info regarding this system.
When a user clicks on new invoice button I assign -1 as the invoice number.
(If you assign last number +1 here there will always be issues due to
the time gap involved in assigning and saving of first row with that value)
The text where invoice number is displayed uses iif

form.header.cash_no.text = "Invoice No. <font color='red'><b>"+
iif(form.minvoice = -1 , "new" , form.minvoice)        + "</b></font> "

So the user does not feel awkward that how come a new number is -1

In the save pushbutton event I use the following line
form.minvoice = iif(form.minvoice>0 , form.minvoice ,form.last()+1 )

i.e. if form.invoice (my invoice number) is greater than 0 i.e valid
then no change otherwise fetch the last Invoice number from the table
and increment it by 1 before using it.

function last()
local mcount
form.salesdatamodule1.last.requery()
mcount = form.salesdatamodule1.last.rowset.fields["numb"].value
if mcount = null
//mcount will be null when there are no rows in the table
        mcount = 0
endif
return mcount


SQL for query last
Select max(invoice_no) as numb from sales WHERE mast <>0

The codes being used are according to my needs and are for example only.
Make changes according to your own need.

There should not be any gaps in invoice numbering and there should not
be duplicates are the two key necessary requirements of an invoicing
system. To achieve this there should be bare minimum time gap between
generating new invoice number and saving the first row so that the next
person who generates new invoice number is assigned a new number.

Regards
Akshat