Is there really any possible way to prevent school shootings?

I know what you mean! Even if they ban guns for everyone, you couldn't get every single gun out there. Then, it would create a blackmarket for guns so whoever has enough to pay for it, will get it. Plus, even without guns, he could have burned down the school, killing a lot more people or bombing the school. So just like you said, there's no way to ensure school safety...Sad but true.