ascending order on invoice number. If so, we need to make Invoice 110 point to Invoice 111 (at RRN8), and we need to make Invoice 111, the new invoice, point to Invoice 118 (at RRN3). This modification is shown in Figure H-22.
Similarly, deleting an invoice is easy. If Invoice 114 is deleted, we simply modify the pointer in the in-voice that is now pointing to Invoice 114. In this case, it is Invoice 112 at RRN5. We give Invoice 112 the pointer that Invoice 114 had before deletion. In this way, Invoice 112 points to Invoice 119, as shown in Figure H-23. We have effectively cut one link out of the chain and welded together the ones it once con-nected.