This rule applies whenever an ``IF`` statement is followed by one or more ``ELSEIF`` statements; the final ``ELSEIF`` should be followed by an ``ELSE`` statement.
The requirement for a final ``ELSE`` statement is defensive programming.
The ``ELSE`` statement should either take appropriate action or contain a suitable comment as to why no action is taken. This is consistent with the requirement to have a final ``OTHER`` clause in a ``SELECT`` statement.
