title: mysql prevent negative numbers
body: <p>Is their an int field in mysql where negative numbers are not allowed? or more specifically if a negative number is inserted into the field it will insert a zero. I ask this because we have a scoring system and we don't allow people to have negative scores. So if their score does reach bellow zero, it will just insert a zero instead. I'm trying to do this without having to query the user's score to check if it will fall bellow zero.</p>