Consider a view branch-cust defined as follows:

create view branch-cust as

select branch-name, customer-name

from depositor, account

where depositor.account-number = account.account-number

Suppose that the view is materialized , that is, the view is computed and stored. Write active rules to maintain the view, that is, to keep it up to date on insertions to and deletions from depositor and account. Do not bother about updates. Write with SQL