How to Convert MySQL Code to PDO Statements for Improved Security and Efficiency?

How to convert MySQL code into PDO statement?

In order to change the initial if statement into a PDO statement, you will need to first establish a connection using PDO. Here's how you can do that:

// Define database connection parameters
$db_host = "127.0.0.1";
$db_name = "name_of_database";
$db_user = "user_name";
$db_pass = "user_password";

try {
    // Create a connection to the MySQL database using PDO
    $pdo = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, FALSE);
} catch (PDOException $e) {
    echo 'Failed to connect to the database: ' . $e->getMessage();
}

Next, you need to modify your existing code to use prepared statements with PDO. Here's an updated version of the code:

// Initialize variables
$id = $_SESSION['u_id'] ?? NULL;
$email = NULL;

if($id) {
    // Prepare the SQL statement
    $sql = "SELECT email FROM users WHERE u_id = :id";
    $query = $pdo->prepare($sql);
    
    // Bind the parameter and execute the query
    $query->bindParam(':id', $id, PDO::PARAM_STR);
    $query->execute();
    
    // Fetch the result
    $row = $query->fetch(PDO::FETCH_OBJ);
    $email = $row->email;
}

// Initialize other variables
$optionOne     = $_POST['optionOne'] ?? "";
$optionTwo     = $_POST['optionTwo'] ?? "";
$newSuggestion = $_POST['new-suggestion'] ?? "";

// Check if the form was submitted
if($newSuggestion and $id and $email and $optionOne and $optionTwo) {
    // Prepare the SQL statement
    $sql = "INSERT INTO suggestions (user_id, email, option_1, option_2) VALUES (:id, :email, :option_1, :option_2)";
    $query = $pdo->prepare($sql);

    // Bind the parameters and execute the query
    $query->bindParam(':id', $id, PDO::PARAM_STR);
    $query->bindParam(':email', $email, PDO::PARAM_STR);
    $query->bindParam(':option_1', $optionOne, PDO::PARAM_STR);
    $query->bindParam(':option_2', $optionTwo, PDO::PARAM_STR);
    $query->execute();
} else {
    echo "All options must be entered.";
}

This updated code uses prepared statements with PDO to improve security and efficiency. It also uses the NULL coalescing operator (??) to assign default values to variables when they are null.

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