如何将此代码从mysqli更改为PDO

Posted 2021-05-06

if (isset($_GET['page_no']) && $_GET['page_no']!="") {
    $page_no = $_GET['page_no'];
    } else {
        $page_no = 1;
        }

    $total_records_per_page = 9;
    $offset = ($page_no-1) * $total_records_per_page;
    $previous_page = $page_no - 1;
    $next_page = $page_no + 1;
    $adjacents = "2"; 

    $result_count = mysqli_query($con,"SELECT COUNT(*) As total_records FROM `products`");
    $total_records = mysqli_fetch_array($result_count);
    $total_records = $total_records['total_records'];
    $total_no_of_pages = ceil($total_records / $total_records_per_page);
    $second_last = $total_no_of_pages - 1; // total page minus 1

    $result = mysqli_query($con,"SELECT * FROM `products` LIMIT $offset, $total_records_per_page");
    while($row = mysqli_fetch_array($result)){
        echo "<tr>
              <td>".$row['productCode']."</td>
              <td>".$row['productName']."</td>
              <td>".$row['MSRP']."</td>
              <td><button type='submit' class='buy'>Buy Now</button></td>
              </tr>";
        }
    mysqli_close($con);
    ?>

我需要将此代码更改为PDO格式。而且我不确定PDO中mysqli_fetch_array的功能是什么。

答案

这是你怎么做的：

// Execute query and fetch a single cell from the result
$total_records = $PDO->query('SELECT COUNT(*) FROM `products`')->fetch(PDO::FETCH_COLUMN);

$total_no_of_pages = ceil($total_records / $total_records_per_page);
$second_last = $total_no_of_pages - 1; // total page minus 1

// prepare a statement with 2 parameters and execute it
$stmt = $PDO->prepare('SELECT * FROM `products` LIMIT ?,?');
$stmt->execute([$offset, $total_records_per_page]);
// PDO results are easily traversable
foreach ($stmt->fetchAll() as $row) {
    echo "<tr>
        <td>".$row['productCode']."</td>
        <td>".$row['productName']."</td>
        <td>".$row['MSRP']."</td>
        <td><button type='submit' class='buy'>Buy Now</button></td>
        </tr>";
}

我用一个准备好的语句替换你的连接查询，你应该总是这样做！

关于获取：您可以逐个遍历记录，或者像我在数组中获取所有记录一样，并在其上获取foreach。有很多不同的方法可以做到这一点。永远记住许多可用的PDO提取选项：https://phpdelusions.net/pdo#fetchall