How to use database query and result paging function in PHP for paging display and page navigation of data?

How to use database query and result paging function in PHP for paging display and page navigation of data?

When developing web applications, it is often necessary to process a large amount of data. Displaying all the data on the page at once will not only affect performance, but also give users a bad experience. Therefore, paging is a very important function for the display of large data sets.

In PHP, using database query and result paging functions can easily realize paging display and page navigation of data. The following will introduce how to use PHP's database query and result paging functions for paging display and page navigation.

First, we need to connect to the database and obtain the data that needs to be displayed. Assuming that the data we want to display is stored in a table named "users", we can use the following code to connect to the database and obtain the data:

<?php
// 连接数据库
$host = "localhost";
$username = "root";
$password = "password";
$dbname = "my_database";
$dsn = "mysql:host=$host;dbname=$dbname";
$pdo = new PDO($dsn, $username, $password);

// 获取数据
$page = isset($_GET['page']) ? $_GET['page'] : 1; // 获取当前页数，默认为第1页
$limit = 10; // 每页显示的记录数
$offset = ($page - 1) * $limit; // 计算偏移量
$sql = "SELECT * FROM users LIMIT $offset, $limit";
$stmt = $pdo->prepare($sql);
$stmt->execute();
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);
?>

In the code, we first define the connection parameters of the database, including Host, username, password, and database name. These parameters are then used to create a PDO object for connecting to the database. Next, we get the current page number through the $_GET super global variable. If no page number is passed, it defaults to page 1. Then, we calculate the offset based on the number of records displayed on each page and the current page number, and use SQL statements to obtain the corresponding data from the database. After obtaining the data, we store it in the $data array for subsequent use.

After obtaining the data, we can display it. The following is a simple display example:

<?php foreach($data as $row): ?>
  <p>ID: <?php echo $row['id']; ?></p>
  <p>Name: <?php echo $row['name']; ?></p>
  <p>Email: <?php echo $row['email']; ?></p>
<?php endforeach; ?>

The above code will traverse each piece of data and display it on the page in an appropriate manner. In practical applications, you can display it according to your own needs.

While displaying data, we also need to provide page navigation so that users can easily browse different pages of data. The following is a simple page navigation example:

<?php
$total = count($data); // 数据总数
$pages = ceil($total / $limit); // 总页数

// 生成翻页导航
echo "<ul class='pagination'>";
for ($i = 1; $i <= $pages; $i++) {
  echo "<li><a href='?page=$i'>$i</a></li>";
}
echo "</ul>";
?>

In the above code, we first calculate the total data volume and calculate the total number of pages based on the number of records displayed on each page. We then generate an unordered list with page-turning links through a loop and display it on the page. Each link contains the corresponding page number parameter so that when the user clicks on the link, he or she can correctly switch to the corresponding page.

To sum up, by using PHP's database query and result paging functions, we can easily implement paging display and page navigation of data. The above example code is just a simple implementation, you can extend and improve it according to your own needs. I hope this article will be helpful to you in paging display and page navigation of data processing in PHP.

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