Retrieving All Data with the fetchAll() Method

The fetchAll() method returns an array containing all of the remaining rows in the result set. Unlike the fetch method, which reads row by row, fetchAll captures all data at once and stores it in a multidimensional array. This is very convenient for smaller tables, as you can get all information with a single call and then easily process it using a foreach loop.

EXAMPLE

<?php
class Database {
    private $server = "localhost";
    private $username = "root";
    private $password = "";
    private $db_name = "pdo_db";
    public $connection;

    public function __construct() {
        try {
            // Added charset=utf8mb4 for character support
            $dsn = "mysql:host=" . $this->server . ";dbname=" . $this->db_name . ";charset=utf8mb4";
            $this->connection = new PDO($dsn, $this->username, $this->password);
            $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        } catch(PDOException $e) {
            die("Connection failed: " . $e->getMessage());
        }
    }

    public function getAllUsers() {
        $statement = $this->connection->prepare("SELECT first_name, last_name FROM users");
        $statement->execute();

        // fetchAll(PDO::FETCH_ASSOC) returns the entire array
        $results = $statement->fetchAll(PDO::FETCH_ASSOC);
        
        $statement->closeCursor();
        return $results;
    }
}

// PART 3: Usage
$db = new Database();
$allUsers = $db->getAllUsers();

foreach ($allUsers as $person) {
    echo "First Name: " . $person['first_name'] . ", Last Name: " . $person['last_name'] . "<br>";
}
?>

RESULT

The result will be displayed here...

Practical Application: We use the fetchAll method when we want to store the data from the database into a variable for later use in a template or when we need to convert the data into JSON format. Check the process at home by following these steps:

Start the Apache and MySQL modules in the XAMPP control panel.
Ensure that the users table with five test records exists within the pdo_db database.
The method returns an array of all rows; if there are no results, it returns an empty array.
Insert the example below into a PHP file and display the entire list of users using a loop.