Blocking of Duplicate Customer Ref Number in AR Invoice

Question

Good Morning Experts,
Just want to know how to block duplicate customer reference number in AR Invoice Entry.  System is currently give message that "Customer ref number already exists in this document type..". 
My set up for Document Remarks Include in Document Settings is BP Reference Number.  Is there any additional set up that needs to be done so that system will block duplicate reference number?
Version SAP 2007A
PL 30
Localisation Australia/New Zealand
Thanks
Sandra

Answer 1

Hi
You can try this sp_transaction notification : Copy the given code to store procedure sp_transaction notification where it says --add code here
if (@object_type = '13' or @object_type = '15')
and (@transaction_type= 'A' or @transaction_type= 'U')
begin
declare @venno as varchar(100)
if @object_type = '15'
begin
select @venno = NumAtCard
from opdn
where docentry =@list_of_cols_val_tab_del
if 1 != (select count(docentry) from ODLN with(nolock) where NumAtCard = @venno)
begin
select @error = 1
select @error_message = 'Duplicate Customer ref no in SO Receipts. ! '
end
end
else
if @object_type = '13'
begin
select @venno = NumAtCard
from opch
where docentry =@list_of_cols_val_tab_del
if 1 != (select count(docentry) from OINV with(nolock) where NumAtCard = @venno)
begin
select @error = 2
select @error_message = 'Duplicate vendor ref no in AR Invoices. ! '
end
end
end
This will block the transaction when you have duplicate customer reference . It will let you put same customer reference in Sales order  but it will block from delivery
<b>Please test it in test environment </b>
Thank you
Bishal