Reading Data with the fetch() Method

The fetch() method is used to retrieve the next row from a result set. This is extremely efficient when working with larger datasets, as we do not load all rows into memory at once, but rather process them sequentially. The method accepts various parameters (modes) that determine the format in which we want to receive the data – most commonly as an associative array (PDO::FETCH_ASSOC).

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

        // fetch(PDO::FETCH_ASSOC) reads row by row
        while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
            echo "User: " . $row['first_name'] . " " . $row['last_name'] . "<br>";
        }
        
        $statement->closeCursor();
    }
}

// PART 3: Usage
$db = new Database();
$db->printAllUsers();
?>

RESULT

The result will be displayed here...

Practical Application: We typically use the fetch method inside a while loop. Each call to the method moves the pointer to the next row until it reaches the end of the results. Check the process at home by following these steps:

Start the Apache and MySQL modules in the XAMPP control panel.
Ensure via phpMyAdmin that the users table with test data exists within the pdo_db database.
The method returns the row as an array or an object; if there are no more rows, it returns false.
Insert the example below into your PHP file and observe the output of all names from the table.