Gun control won’t stop these attacks. But I know when I was in high school, they started having rent-a-cops and later cops patrolling the halls and grounds. They limited access into the schools and later on (after I graduated) started with metal detectors, etc. When my kids started going to school, you had to be “buzzed in” to be able to enter. There was an intercom you had to use to identify yourself. And the doors were within sight of the office so if anyone tried defeating the lock, they could call the cops immediately. I believe these are “common sense” measures that can help.