A view is defined as: CREATE VIEW V AS SELECT dept_id, AVG(salary) AS avg_sal FROM Employees GROUP BY dept_id; Can this view be used directly in an UPDATE statement to modify the underlying Employees.salary values, and why?

A view is updatable only when SQL can unambiguously translate a modification on the view back into a modification on specific rows of the underlying base table(s). Views containing aggregate functions (like AVG, SUM, COUNT), GROUP BY, DISTINCT, or certain multi-table joins/set operations generally violate this requirement, because a single aggregated value (like a department's average salary) doesn't correspond to any single underlying row — there is no well-defined way to decide how a change to avg_sal should be distributed among the individual employee salary values that produced it. This makes such a view read-only in practice, even though views in general can sometimes be updatable (e.g., simple views on a single table without aggregation).