Deleting and modifying tables with views
Modifying views
Instruction
Let's get started then. Suppose we have the following table and a view based on it:
CREATE TABLE gym ( id integer PRIMARY KEY, name varchar(32), city varchar(32), monthly_fee decimal(5, 2), max_capacity integer );
CREATE VIEW big_gyms_london AS SELECT id, name, max_capacity FROM gym WHERE city = 'London' AND max_capacity > 50;
At some point we decide that we no longer need the view. What can we do then? Take a look:
DROP VIEW big_gyms_london;
As you can see, deleting a view in SQL is very simple.
Exercise
You're given a table with courses offered at a university:
CREATE TABLE course ( id integer PRIMARY KEY, name varchar(128), lecturer varchar(128), ects_points integer, max_students integer, has_exam boolean );
There's also a view which selects courses run by professor John Smith:
CREATE VIEW courses_prof_smith AS SELECT id, name, max_students, has_exam FROM course WHERE lecturer = 'John Smith';
Your task is to drop this view.
