Thesis-database view update-provision

I: DB2 rules:
(1) If the view is exported from more than two basic tables, the view cannot be updated.
(2) If a field in a view comes from a field expression or constant, insert and update operations on the view are not allowed, but delete operations are allowed.
(3) If the field of the view comes from the set function, the view cannot be updated.
(4) If the view definition contains a group by clause, the view cannot be updated.
If the view definition contains a distinct phrase, the view cannot be updated.
If the view definition contains nested queries and the tables involved in the from clause of the inner query are also the basic tables for exporting the view, the view cannot be updated.
You cannot update a view defined on a view that cannot be updated.