php安全操作sql函数，php，服务器内置函数

Title: Secure SQL Operations in PHP: A Guide to Server Built-in Functions

Introduction:

In modern web development, handling user input securely is of utmost importance to ensure the integrity and confidentiality of data stored within a database. PHP, being one of the most popular languages for web development, provides a range of server built-in functions that aid in safe SQL operations. In this article, we will explore these functions and their best practices to ensure secure SQL operations in PHP.

1. Prepared Statements:

Prepared statements are the most effective way to prevent SQL injection attacks. Instead of directly concatenating user input into SQL queries, we can use prepared statements with placeholders, which are then bound with the actual values at execution time. By separating the data from the query, we can prevent malicious input from causing unintended SQL operations. PHP provides the `mysqli` and `PDO` extensions for executing prepared statements.

Example using mysqli:

```

$mysqli = new mysqli("localhost", "username", "password", "database");

$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");

$stmt->bind_param("s", $username);

$username = $_POST['username'];

$stmt->execute();

$result = $stmt->get_result();

```

Example using PDO:

```

$pdo = new PDO("mysql:host=localhost;dbname=database", "username", "password");

$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");

$stmt->execute(['username' => $username]);

$result = $stmt->fetchAll();

```

2. Escaping User Input:

In situations where prepared statements are not feasible, we can sanitize user input using built-in functions such as `mysqli_real_escape_string()` or `PDO::quote()`. These functions escape special characters in user input, preventing them from being interpreted as SQL commands. However, it is important to note that manual escaping is error-prone and should be used as a last resort when prepared statements are not applicable.

Example using mysqli:

```

$mysqli = new mysqli("localhost", "username", "password", "database");

$username = mysqli_real_escape_string($mysqli, $_POST['username']);

$query = "SELECT * FROM users WHERE username = '$username'";

$result = $mysqli->query($query);

```

Example using PDO:

```

$pdo = new PDO("mysql:host=localhost;dbname=database", "username", "password");

$username = $pdo->quote($_POST['username']);

$query = "SELECT * FROM users WHERE username = $username";

$result = $pdo->query($query);

```

3. Password Hashing:

Storing passwords securely is crucial to protect user data. In PHP, the `password_hash()` function can be used to hash passwords using bcrypt or Argon2 algorithms, which are considered secure for password hashing. This function automatically generates a unique salt for each hashed password, making it resistant to rainbow table attacks.

Example:

```

$password = $_POST['password'];

$hashedPassword = password_hash($password, PASSWORD_DEFAULT);

```

To verify the password, we can use the `password_verify()` function:

```

$hashedPassword = $row['password']; // Retrieved from the database

$password = $_POST['password'];

if (password_verify($password, $hashedPassword)) {

// Password is correct

} else {

// Password is incorrect

}

```

Conclusion:

Securing SQL operations is crucial to prevent SQL injection attacks and protect user data. In this article, we have explored server built-in functions in PHP that aid in safe SQL operations. It is important to prioritize prepared statements over manual escaping and to use secure password hashing techniques. By implementing these best practices, developers can ensure the integrity and confidentiality of their databases and protect against potential breaches. 如果你喜欢我们三七知识分享网站的文章， 欢迎您分享或收藏知识分享网站文章 欢迎您到我们的网站逛逛喔！https://www.ynyuzhu.com/