How do I convert MySQL code to PDO statements?

How to convert MySQL code into PDO statement?

When working with databases in PHP, it's often necessary to convert MySQL code into PDO (PHP Data Objects) statements. PDO provides a consistent and secure way to interact with databases, regardless of the underlying driver. This guide will show you how to convert your MySQL code into PDO statements.

Make a connection

The first step is to make a connection to the database using PDO. Here's an example of how to do it:

$db_host = "127.0.0.1";
$db_name = "database_name";
$db_user = "username";
$db_pass = "password";

$pdo = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);

Updating your code

Once you have a PDO connection, you can start converting your MySQL code into PDO statements.

Prepared statements with mysqli and PDO

Prepared statements are a secure way to execute queries that contain user-supplied data. They prevent SQL injection by binding the data to the query before it is executed.

Here's an example of a prepared statement in MySQLi:

$sql = "SELECT * FROM users WHERE username = ? AND password = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("ss", $username, $password);
$stmt->execute();
$result = $stmt->get_result();

Here's the same query in PDO:

$sql = "SELECT * FROM users WHERE username = ? AND password = ?";
$stmt = $pdo->prepare($sql);
$stmt->bindParam(1, $username, PDO::PARAM_STR);
$stmt->bindParam(2, $password, PDO::PARAM_STR);
$stmt->execute();
$result = $stmt->fetchAll();

Updated code

Here's an example of how to convert the MySQL code from the question into PDO statements:

$id = $_SESSION['u_id'] ?? NULL;

if ($id) {
    $sql = "SELECT email FROM users WHERE u_id = ?";
    $stmt = $pdo->prepare($sql);
    $stmt->execute([$id]);
    $email = $stmt->fetchColumn();
}

$email = $email ?? "";
$suggestions = selectAll($table);

$optionOne = $_POST['optionOne'] ?? "";
$optionTwo = $_POST['optionTwo'] ?? "";
$newSuggestion = $_POST['new-suggestion'] ?? "";

if ($newSuggestion && $id && $email && $optionOne && $optionTwo) {
    $sql = "INSERT INTO suggestions (user_id, email, option_1, option_2) VALUES (?, ?, ?, ?)";
    $stmt = $pdo->prepare($sql);
    $stmt->execute([$id, $email, $optionOne, $optionTwo]);
} else {
    echo "All options must be entered";
}

Summary

Converting MySQL code into PDO statements is a relatively straightforward process. By following the steps outlined in this guide, you can easily migrate your code to PDO and take advantage of its benefits, such as improved security and performance.

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