How to execute sql delete statement in php

For developers, how to correctly execute SQL delete statements is very important. PHP is a widely used programming language that provides multiple methods to delete data from the database. This article will introduce how to use PHP to execute SQL delete statements.

1. Using the MySQLi extension

MySQLi is an extension in PHP that provides the functionality to communicate with the MySQL database. SQL delete statements can be easily executed using the MySQLi extension.

The steps are as follows:

1) Connect to the MySQL database

To use the MySQLi extension to execute SQL delete statements, you first need to connect to the MySQL database. This can be achieved through the mysqli_connect() function.

Example:

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDB";

// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检查连接是否成功
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

2) Execute SQL delete statement

Once you successfully connect to the MySQL database, you can use the connection object to execute SQL delete statement. Use the mysqli_query() function, passing the SQL statement to be executed as a parameter.

Example:

$sql = "DELETE FROM customers WHERE id=1";

if (mysqli_query($conn, $sql)) {
    echo "Record deleted successfully";
} else {
    echo "Error deleting record: " . mysqli_error($conn);
}

2. Using PDO

PHP Data Objects (PDO) are another way to perform database operations in PHP. PDO supports a variety of databases, including MySQL, SQLite, Oracle, etc. Similar to the MySQLi extension, SQL delete statements can also be easily executed using PDO.

The steps are as follows:

1) Connect to the MySQL database

To use PDO to execute SQL delete statements, you first need to connect to the MySQL database. This can be achieved through PDO objects.

Example:

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "myDB";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully"; 
} catch(PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

2) Execute SQL delete statement

Once you successfully connect to the MySQL database, you can use the PDO object to execute SQL delete statement. Use the prepare() function and execute() function to pass the SQL statement to be executed as a parameter.

Example:

$sql = "DELETE FROM customers WHERE id=:id";
$stmt = $conn->prepare($sql);
$stmt->bindParam(':id', $id);

if ($stmt->execute()) {
    echo "Record deleted successfully";
} else {
    echo "Error deleting record";
}

Summary

Using PHP to execute SQL delete statements can be achieved through MySQLi extension and PDO. No matter which method you use, you need to first connect to the database and then use the appropriate function to execute the SQL delete statement.

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