Fetch value of fieldname from another doctype

Frappe Framework Print Formats
7

Hi @Gavin_Ji! Had similar use case but with PO. I wanted to auto populate it in Parent in Purchase Receipt. What I did is I created Purchase_Order fieldname. So for Sales Order, please make you field name to Sales_Order. This will be auto-populated when crated DN from SO. Also, if this wont work, you can create a pyhton script validaiton on save:

def so_validate(doc, method):

    so_no = frappe.get_doc("""Select agaisnt_sales_order from `tabDelivery Note Item` where parent = %s""", 
                           doc.parent)
    
    doc.so_no = so_no

Hope this helps!