save one master and multiple detail records on single button click

as salaam alykum,

i am working on project  where i have one master table "PURCHASE_ORDER" with fields

order_no  as primary key

vendor_id

order_date

and i have a detail table called "PURCHASE_ORDER_DETIALS" with fields 

sno,order_no,item,qty,rate.

i am supposed to create a master detail form 

where i am supposed to accept an order from an vendor with multiple items.

i.e the form shoud accept one master record and multiple detail records and then either save all  of them or discard all of them(both master and multiple detail records).

its urgent plz