以下是bind_param PHP的方法有什么区别

Question

I'm just getting over using the singleton approach and am starting to get into prepared statements... I'm racking my brain on why one version of this works and one does not when, to me, they seem to be the same thing... I really want it to work the second way in order to meet my end goal.

This works:

call_user_func_array(array($stmt, 'bind_param'), array("i", 2));

This does not:

$params = array("i", 2);
call_user_func_array(array($stmt, 'bind_param'), $params);

Answer 1

You are probably getting an error message like

mysqli_stmt::bind_param() expected to be a reference, value given in...

The problem is that bind_param() in PHP 5.3+ requires array values as reference while 5.2 works with real values.

From the docs:

Care must be taken when using mysqli_stmt_bind_param() in conjunction with call_user_func_array(). Note that mysqli_stmt_bind_param() requires parameters to be passed by reference, whereas call_user_func_array() can accept as a parameter a list of variables that can represent references or values (ref).

---

One solution is to create an array of references

$params = array("i", 2);
$tmp = array();
foreach($params as $key => $value) {
    $tmp[$key] = &$params[$key];
}
call_user_func_array(array($stmt, 'bind_param'), $tmp); 

and another similar solution is

function refValues($arr){ 
    if (strnatcmp(phpversion(),'5.3') >= 0) //Reference is required for PHP 5.3+ 
    { 
        $refs = array(); 
        foreach($arr as $key => $value) 
            $refs[$key] = &$arr[$key]; 
        return $refs; 
    } 
    return $arr; 
} 

$params = array("i", 2);
call_user_func_array(array($stmt, 'bind_param'), refValues($params));