Disallow NULL values with SET NOT NULL
The professors table is almost ready now. However, it still allows for NULLs to be entered. Although some information might be missing about some professors, there's certainly columns that always need to be specified.
Questo esercizio fa parte del corso
Introduction to Relational Databases in SQL
Esercizio pratico interattivo
Prova a risolvere questo esercizio completando il codice di esempio.
-- Disallow NULL values in firstname
___ ___ professors
ALTER COLUMN ___ SET NOT NULL;