How to ensure security on campus

In just over a month, five men have attacked schoolchildren in five different provinces, killing eight and injuring at least 55 of them. To prevent such attacks from recurring, the authorities have strengthened security checks in and around schools across the country.
I have lived for 22 years in the United States, where campus shootings are not uncommon. A person who has never seen a campus attack cannot possibly imagine how terrible it is. Though developed countries spend relatively more money to preempt such attacks, none can claim that its campuses are hundred percent safe. That, however, should not deter local governments and communities from trying to reach a consensus on how to ensure campus safety.
In the US, counselors, normally with psychology or psychiatry degrees, help disturbed students solve their problems. And in case of an attack, they help shocked students overcome their trauma.