How to correctly delete Purchase Order lines and headers in code

I currently have an application that uses the AxPurchTable and AxPurchline to create purchase orders.

Two questions,

1. After calling "AxPurchLine.doSave(),"  on an unposted PO, can you safely delete a purchase order line, and all associated database records, by calling AxPurchLine.delete()?

2. On an unposted purchase order, can you safely delete a purchase order header by calling AxPurchTable.delete()? Or, should I be cancelling the purchase order instead of deleting it?