php – MySQLi bind_param()参考

我试图动态地将几个参数传递给bind_param()函数.

这是我收到的错误：

Warning: Parameter 2 to mysqli_stmt::bind_param() expected to be a
reference, value given

码：

$con = new MysqLi('localhost',USER,PASS,DBS);

if(MysqLi_connect_errno()) {
error(MysqLi_connect_errno());
}

$con -> set_charset("utf8");

/*inside*/

$type='';

$query='SELECT bugID FROM bug';

if(!empty($_GET['cena'])) {

    $build[]='uCena=?';

    $type.='i';
    $val[]=$_GET['cena'];

}

if(!empty($_GET['popust'])) {

    $build[]='uPopust=?';

    $type.='i';
    $val[]=$_GET['popust'];

}

if(!empty($build)) {

    echo $query .= ' WHERE '.implode(' AND ',$build);
}

$new = array_merge(array($type),$val);
foreach($new as $key => $value)
{
    $tmp[$key]=&$new[$key];

    }

echo '<br/><br/>';

foreach ($new as $new ){

    echo "$new<br/>";
}

if ($count = $con->prepare($query)) {

    call_user_func_array(array($count,'bind_param'),$tmp);
    $count->execute();
    $cres = $count->fetch_row();

    $count -> close();

} else error($con->error);


/*inside*/

$con -> close();

解决方法:

我很抱歉这样说,但你的代码很糟糕.它是不可读的,并且在生产环境中很难维护.

一个例子：你在哪里使用这些行：

foreach($new as $key => $value)
{
    $tmp[$key]=&$new[$key];
}

你可以使用：

foreach($new as $key => $value)
{
    $tmp[$key]= $value;
}

哪个会显示你对foreach声明的理解.此外,使用比$tmp和$new更多的描述性变量名称可以提高代码的可读性.您的代码还有很多问题,但让我们关注这个问题.

主要问题在于这一行：

if ($count = $con->prepare($query)) {

这一行：

call_user_func_array(array($count,'bind_param'),$tmp);

MysqLi :: prepare()返回一个 MysqLi_statement(如here所述),而不是某种计数.如果需要确定参数的数量,请尝试使用$count = count($tmp).

您看到的错误是您使用call_user_func_array()的结果.如PHP.net page on bind_param所述：

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.

同一页面上的评论中提供了最佳解决方案：

Coming to the problem calling MysqLi::bind_param() with a dynamic number of arguments via call_user_func_array() with PHP Version 5.3+, there’s another workaround besides using an extra function to build the references for the array-elements.
You can use Reflection to call MysqLi::bind_param(). When using PHP 5.3+ this saves you about 20-40% Speed compared to passing the array to your own reference-builder-function.

例：

<?PHP 
$db     = new MysqLi("localhost","root","","tests"); 
$res    = $db->prepare("INSERT INTO test SET foo=?,bar=?"); 
$refArr = array("si","hello",42); 
$ref    = new ReflectionClass('MysqLi_stmt'); 
$method = $ref->getmethod("bind_param"); 
$method->invokeArgs($res,$refArr); 
$res->execute();  
?>

希望这可以帮助.

php – MySQLi bind_param()参考

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