One way to do this would be to set the permissions on the form in which the menus exist. Then you could do something like: (very simplistic code)
int userPermission = [get_user_permission_level];
if (userPermission == 1)
mnuItem1.visible = true;
mnuItem2.visible = false;
else if (userPermission == 2)
You'll need to work out how to do this in a more sophisticated way but this should get you going.
In terms of storing the permissions in the database presumably your schema has a table that describes the users? Add a column in there that holds the permissions level and this might be a reference to a table that holds a list of permission levels.