Invoice creation

 Hi,

We are on Oracle E-Business Suite R12.1.3  .

Recently we have noticed that the system is allowing to create invoice numbers with a space after the number. 

for example, I can create an invoice with number 1234, and I can also create a same invoice number with a space after the number, 1234<space> , next we can create another invoice number with two spaces  1234<space><space> .

As the invoice_num column is created as varchar2 it's taking space as a character.

is there any way to avoid creating invoices with spaces after the number ?

Please advice.

Thanks

Oliver