Reload Problem, user tend to submit data twice

[eluser]xwero[/eluser]
Before you validate you could check if the same input is already inserted

Code:

//model
function check_duplicate($post)
{
    $query = $this->db->query('select count(*) as check from table where field1=? and field2=?',array($post['field1'],$post['field2']));
    $row = $query->row();
    return ($row->check == 0)?false:true;
}

You could abstract it more so you can use it for all your tables.
You could even make a ajax validation for this.