How can I prevent SQL injection in PHP

How to Prevent SQL Injection

SQL injection attacks are serious threat to the security of any website that uses a database. They occur when a malicious user inputs malicious SQL commands into website fields, potentialy compromising sensitive information or gaining full access to the database .

To safeguard against these attacks, utilizing prepared statements with parameterized queries in PHP is key . Prepared statements are pre compiled SQL commands that can be repeatedly executed with varying parameters. Using this method, you can guarantee that all user input is properly secured and any malicious attempts to inject SQL will be blocked .

Use PDO Objects

To use a prepared statement with a parameterized query in PHP, you can use the PDO (PHP Data Objects) library . Generate a fresh PDO object and initiate a connection to the your database :

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

After that, generate a prepared statement by utilizing the prepare function of the PDO Object .

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

Note that the :name placeholder represents a parameter that will be supplied when the statement is executed .

To combine a value with the parameter, use the bindValue method of the statement object:

$stmt->bindValue(':name', $name, PDO::PARAM_STR);

Here, $name is the user suplied value that will be passed to the :name parameter when the statement is executed . The PDO::PARAM_STR constant tells PDO that the parameter is a string value.

Finally, execute the prepared statement using the execute method:


You can then fetch the result using one of the fetch methods of the statement object, such as fetch or fetchAll.

Preventing SQL injection attacks in PHP is crucial for website security . Not only should you use prepared statements with parameterized queries, but also properly sanitize and validate all user input, and connect to the database with the minimum necesary privileges .

Here few more tips to prevent SQL Injection attacks :

  • Escape special characters with mysqli_real_escape_string, especially in older versions of PHP.
  • Escape HTML characters with htmlspecialchars to defend against cross-site scripting attacks ( XSS ) .
  • Validate user input to only allow necessary data in the database.
  • Limit database access privileges.
  • Keep your PHP and database software updated with the latest security improvements.

SQL injection attacks give a serious risk to web applications and their databases. with these tips and other best methods , you can ensure the security of your website and protect against SQL injection and other security threats.