How to delete php database

php's database needs to be connected to the database first, and then use SQL statements to perform the delete operation. Detailed introduction: 1. First define a SQL statement, use the DELETE FROM statement to specify the table and conditions to be deleted, and then use the $conn->query() method to execute the SQL statement. If the execution is successful, "data deletion successful" will be output. , otherwise an error message will be output; 2. Use the PDO constructor to connect to the database. Then use the $conn->exec() method to execute SQL statements and so on.

The operating environment of this tutorial: windows10 system, php8.1.3 version, DELL G3 computer.

PHP is a widely used server-side scripting language used for developing dynamic websites and applications. During the development process, you often need to interact with the database, including inserting, querying, updating, and deleting data. This article will focus on how to delete data in the database using PHP.

In PHP, you can interact with the database in a variety of ways, including MySQL, SQLite, Oracle, etc. No matter which database you use, the basic principles of deleting data are the same. The following will take the MySQL database as an example to introduce in detail how to use PHP to delete data.

First, you need to make sure you are connected to the database. You can use PHP's built-in mysqli or PDO extension to connect to the database. The following is a sample code for connecting to a MySQL database using the mysqli extension:

$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "mydb";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// 检查连接是否成功
if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

After the connection is successful, you can use SQL statements to delete data in the database. The following is a sample code that uses the mysqli extension to perform a delete operation:

$sql = "DELETE FROM users WHERE id=1";
if ($conn->query($sql) === TRUE) {
echo "数据删除成功";
} else {
echo "数据删除失败: " . $conn->error;
}
$conn->close();
?>

In the above code, a SQL statement is first defined, using DELETE The FROM statement specifies the table and conditions to delete. Then use the $conn->query() method to execute the SQL statement. If the execution is successful, "Data deleted successfully" will be output, otherwise an error message will be output.

In addition to using the mysqli extension, you can also use the PDO extension to perform delete operations. The following is a sample code to perform a delete operation using PDO extension:

$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "mydb";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, 
$password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "DELETE FROM users WHERE id=1";
$conn->exec($sql);
echo "数据删除成功";
} catch(PDOException $e) {
echo "数据删除失败: " . $e->getMessage();
}
$conn = null;
?>

In the above code, first connect to the database using the PDO constructor. Then use the $conn->exec() method to execute the SQL statement. If the execution is successful, "Data deleted successfully" will be output, otherwise an error message will be output.

To summarize, using PHP to delete data in the database requires first connecting to the database, and then using SQL statements to perform the deletion operation. This function can be easily achieved whether using mysqli or PDO extension. By mastering these basic knowledge, you can better utilize PHP to interact with databases and develop more powerful websites and applications.

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