Instruction
Fabulous work. You may now be wondering: can I add a new column with the NOT NULL constraint to a table if it already has some rows? Well, let's find out!
Exercise
Try to run the template code. Do you think it will succeed?

Fabulous work. You may now be wondering: can I add a new column with the NOT NULL constraint to a table if it already has some rows? Well, let's find out!
Try to run the template code. Do you think it will succeed?
