Will we ever be able to stop this from happening again? The answer is no. There are just too many lunatics in this world to stop this kind of tragedy. Are more gun control laws going to prevent this kind of tragedy from occurring again? Absolutely not! More gun control will only affect those who actually follow the law.
The best way to stop or at least slow down future shooters is to allow those school administrators and teachers the ability to carry concealed firearms on their person while at school if they so choose. Let's face the facts, usually by the time the police arrive at these shootings many lives are already lost and the shooter is dead by a self-inflected gun shot. At least armed school administrators and teachers have a fighting chance to save not only their own life, but the lives of the innocent children.