We can use Create or Replace option to create views instead of dropping the view and recreating it, as with this option the privileges granted on the view are preserved, but the dependent stored programs and view become invalid.
You can use DML operations on a view if the view does not include Group by, Start with, Connect by, Distinct clauses or any subqueries and set operations(Union, union all, intersect and minus).
A statement level trigger is fired only once for a statement.
To make it even simpler, lets consider the statement: UPDATE account_current SET balance = balance 100 WHERE balance 100000; Executing this statement may affect more than one rows.
This common state is established at the start of triggering statement and is destroyed after completion of trigger (regardless of trigger being in error or not).
If same had to be done without compound-trigger, it might have been required to share data using packages.