动态 bindVars 的用法

private function bindVars($stmt,$params) {
    if ($params != null) {
        $types = '';                        //initial sting with types
        foreach($params as $param) {        //for each element, determine type and add
            if(is_int($param)) {
                $types .= 'i';              //integer
            } elseif (is_float($param)) {
                $types .= 'd';              //double
            } elseif (is_string($param)) {
                $types .= 's';              //string
            } else {
                $types .= 'b';              //blob and unknown
            }
        }
 
        $bind_names[] = $types;             //first param needed is the type string
                                            // eg:  'issss'
 
        for ($i=0; $i<count($params);$i++) {//go through incoming params and added em to array
            $bind_name = 'bind' . $i;       //give them an arbitrary name
            $$bind_name = $params[$i];      //add the parameter to the variable variable
            $bind_names[] = &$$bind_name;   //now associate the variable as an element in an array
        }
 
                                            //call the function bind_param with dynamic params
        call_user_func_array(array($stmt,'bind_param'),$bind_names);
    }
    return $stmt;                           //return the bound statement