Cursor Stability isolation

A reader with Cursor Stability isolation acquires a shared lock on the row that is currently fetched. This action assures that no other user can update the row until the user fetches a new row.

In the example for a cursor in Locks placed for cursor stability, at fetch a row the database server releases the lock on the previous row and places a lock on the row being fetched. At close the cursor, the server releases the lock on the last row.
Figure 1: Locks placed for cursor stability
set isolation to cursor stability
declare cursor for SELECT * FROM customer
open the cursor
while there are more rows
   fetch a row
   do work
end while
close the cursor

If you do not use a cursor to fetch data, Cursor Stability isolation behaves in the same way as Committed Read. No locks are actually placed.