How to delete a piece of data by clicking a button in php

PHP is a popular server-side programming language that has a wide range of applications, including deleting data from databases. In this article, we will learn how to write code using PHP to delete data from a MySQL database when the user clicks a button. The specific implementation method is as follows:

First, you need to create a PHP file named "delete.php". This file will contain code to delete the required data from the database.

In this file, we need to get the connection information from the MySQL database so that we can access the database when needed. This information typically includes hostname, username, password, and database name. Before connecting to the database, we need to define these variables as follows:

$host = "localhost"; //主机名
$username = "root"; //用户名
$password = ""; //密码
$dbname = "mydatabase"; //数据库名称

Next, we need to use PHP’s mysqli extension to connect to the database.

$conn = mysqli_connect($host, $username, $password, $dbname) or die("连接失败:" . mysqli_connect_error());

In the above code, we use the mysqli_connect function to connect to the MySQL database. If the connection fails, the die function is called to print error information and terminate the program. If the connection is successful, a connection variable named "$conn" will be created, which we will use for subsequent operations.

Now let us write the code to delete the data from the database. In this example, we will use a POST request to get the ID of the data the user wants to delete. After this, we will query the database to find and delete the record with this ID. Below is the code to delete the data:

if(isset($_POST['delete_id'])) {
    $id = $_POST['delete_id'];
 
    $sql = "DELETE FROM mytable WHERE id = '$id'";
 
    if(mysqli_query($conn, $sql)) {
        echo "该数据已成功删除。";
    } else {
        echo "删除数据时发生错误。" . mysqli_error($conn);
    }
}

In the above code, we first check whether the "delete_id" variable in the POST request is set. If set, we store the value of this variable in a new variable called "$id".

Next, we will write a SQL statement named "$sql" to delete records with a specific ID. In this example, we want to delete the record with a specific ID in the data table named "mytable". If the delete operation is successful, a success message will be output using PHP's "echo" statement; otherwise, an error message will be output.

Now, we create an HTML file named "index.php" that contains the data to be deleted from the database. We place a table in this file that contains the unique ID of each data, and an action cell called "Delete" button for deleting the data. The following is a code example:

<table>
    <thead>
        <tr>
            <th>ID</th>
            <th>名称</th>
            <th>描述</th>
            <th> </th>
        </tr>
    </thead>
    <tbody>
        <?php
            //查询数据表中的所有数据
            $query = "SELECT * from mytable";
            $result = mysqli_query($conn, $query);
 
            while($row = mysqli_fetch_assoc($result)) {
                $id = $row['id'];
                $name = $row['name'];
                $description = $row['description'];
 
                echo "<tr>";
                echo "<td>$id</td>";
                echo "<td>$name</td>";
                echo "<td>$description</td>";
                echo "<td><form method=&#39;POST&#39; action=&#39;delete.php&#39;><input type=&#39;hidden&#39; name=&#39;delete_id&#39; value=&#39;$id&#39;><input type=&#39;submit&#39; value=&#39;删除&#39;></form></td>";
                echo "</tr>";
            }
        ?>
    </tbody>
</table>

In the above code, we use MySQL's "SELECT" command to get all the data in the database and store the results in a result variable called "$result". A loop will be used to iterate through that result and extract the ID, name and description of the data and add them to each row in the table.

Also note that in the cell named "Delete" we placed a button containing a form containing a hidden input field with the ID of the data to be deleted. This form is a POST request button and sends the request to a PHP file named "delete.php".

At this point, our code is ready. Open this file in a browser and you can see a table with the data to be deleted, and an action cell named "Delete" in each row.

When you click the button, it will send a POST request and call the "delete.php" file to delete the data with the selected ID. If the operation is successful, a success message will be displayed on the screen.

In summary, we have learned how to use PHP to write code to delete data in the MySQL database. While this is just a basic example, it provides a good starting point upon which you can freely build more complex functionality.

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