SQL view is said to be updatable (that is, inserts, updates or deletes can be applied on the view) if which of the following conditions are satisfied by the query defining the view?
1.
The select clause contains only attribute names of the relation, and does not have any expressions, aggregates, or distinct specification.
2.
The from clause has only one database relation.
3.
The query does not have a group by or having clause.
4.
All of the mentioned
