PHP PDO fetchAll（）空数组

Question

我有一个小小的webprojekt。我用OOP PHP编写的第一个项目，因此我需要你的帮助。

我的项目： 有一个带有数据库配置设置的config.ini。

db_connection.php

<?php

/**
 *  Database connection File 
 *
 *  Database connection
 *
 */
    //read the .ini file and create an assoziative array
    $db = parse_ini_file("config.ini");

    $db_user = $db['user'];
    $db_pass = $db['pass'];
    $db_name = $db['name'];
    $db_host = $db['host'];
    $db_type = $db['type'];
    $db_port = $db['port'];

    try
    {
        $pdo = new PDO('mysql:host='. $db_host .';port=' . $db_port . ';dbname='.$db_name, $db_user, $db_pass);
        echo "Connected!";
    }
    catch (PDOException $e)
    {
        exit('Error Connecting To DataBase');
    }

database.php中

<?php
/**
 *  Database queries 
 *
 *  Database queries with DROPDOWN-VALUES that are used in HTML-Template to select distinct groups of devices.
 *
 *
 */
    class database
    {
        function __construct($pdo)
        {
            $this->pdo = $pdo;
        }
        //SQL-QUERY of all devices incl. credits and timestamps
        //DROPDOWN VALUE 1
        function getAllData()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices which correspond to the searchword incl. credits and timestamps
        //SEARCHWORD
        function searchword($searchword)
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID
                                          WHERE g.Hersteller LIKE '$searchword'
                                          OR g.Typ LIKE '$searchword'
                                          OR g.Version LIKE '$searchword'
                                          OR u.Firstname LIKE '$searchword'
                                          OR u.Lastname LIKE '$searchword' ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices that are not available including timestamps, firstname and lastname
        //DROPDOWN VALUE 2
        function notAvailable()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM User u
                                          LEFT JOIN Verliehen v
                                          ON u.UID = v.UID
                                          LEFT JOIN Geraet g
                                          ON v.GID = g.GID
                                          WHERE u.GID = g.GID ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices where "Art" is like 'Tablet' incl. credits and timestamps
        //DROPDOWN VALUE 3
        function tablet()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID
                                          WHERE g.Art LIKE 'Tablet' ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices where "Art" is like 'Smartphone' incl. credits and timestamps
        //DROPDOWN VALUE 4
        function smartphone()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID
                                          WHERE g.Art LIKE 'Smartphone' ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices where "Art" is like 'MP3-Player' incl. credits and timestamps
        //DROPDOWN VALUE 5
        function mp3Player()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID
                                          WHERE g.Art LIKE 'MP3-Player' ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }
        //SQL-QUERY of all devices where "Art" is like 'ebook Reader' incl. credits and timestamp
        //DROPDOWN VALUE 6
        function ebookReader()
        {
            $query = $this->pdo->prepare("SELECT g.Hersteller, g.Typ, g.Version, g.Art, v.Zeit, u.Firstname, u.Lastname
                                          FROM Geraete g
                                          LEFT JOIN Verliehen v
                                          ON g.GID = v.GID
                                          LEFT JOIN User u
                                          ON u.UID = v.UID
                                          WHERE g.Art LIKE 'ebook Reader' ; " ) ;
            $query->execute();
            return $query->fetchAll();
        }


    }

的index.php

<?php
/**
 *  Index File 
 *
 *  require of db_connection and database
 *
 */
    require_once 'db_connection.php';
    require_once 'database.php';
    $dbh = new database($pdo);
    $rows = $dbh->getAllData();

    var_dump($rows);

现在我的控制台和我的浏览器只显示我：已连接！数组（0）{}

怎么了？