PDO数据库不向数据库添加项目

Question

I have just got a school assignment to practice PDO. The problem is i seem to get it to connect to database but can't get it to insert or count rows in database. This might be a possible duplicate question did try to search for answers but might just been asking wrong questions.

<?php
 include("db.class.php");

 class uppClass extends Database {

    function __construct() {
        parent::__construct();
    }

    public function countUsers() {
        $stmt = $this->connection->prepare("SELECT * FROM users LIMIT 500");
        $stmt->execute();
        return count( $stmt->fetchAll(PDO::FETCH_ASSOC) );
    }

}
?>

next class handles the pdo connection

<?php
include("db-details.php");

class Database {

    public $connection;

    /**
     * Opens a connection to the DB
     */

    public function __construct() {
        try {
            $this->connection = new PDO("mysql:host=$this->DATABASE_ADDRESS;dbname=$this->DATABASE_NAME;", DATABASE_USERNAME, DATABASE_PASSWORD);
            $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
            $this->connection->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
        } catch (PDOException $e) {
            echo 'Connection failed: ' . $e->getMessage();
        }
    } 

}
?>

Answer 1

To count the rows using PDO you can use this.

public function countUsers() {
    $stmt = $this->connection->prepare("SELECT * FROM users LIMIT 500");
    $stmt->execute();
    $stmt->fetchAll(PDO::FETCH_ASSOC); 
    return $stmt->rowCount();
}