diff --git a/backend/app.py b/backend/app.py
index 52b8f1e..3fe1d3f 100755
--- a/backend/app.py
+++ b/backend/app.py
@@ -1,7 +1,5 @@
 from flask import Flask, request, jsonify, g, redirect, url_for, session as flask_session, render_template, flash
 from flask_cors import CORS
-from flask_sqlalchemy import SQLAlchemy
-from flask_migrate import Migrate
 from werkzeug.security import generate_password_hash, check_password_hash
 from functools import wraps
 import jwt
@@ -11,11 +9,11 @@ import json
 import logging
 import uuid
 import asyncio
+import sqlite3
 from logging.handlers import RotatingFileHandler
 from datetime import timedelta
 from typing import Dict, Any, List, Optional, Union
 from dataclasses import dataclass
-import sqlite3
 from tapo import ApiClient
 from dotenv import load_dotenv
 
@@ -28,8 +26,7 @@ CORS(app, supports_credentials=True)
 
 # Konfiguration
 app.config['SECRET_KEY'] = os.environ.get('SECRET_KEY', 'dev_secret_key')
-app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URL', 'sqlite:///myp.db')
-app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+app.config['DATABASE'] = os.environ.get('DATABASE_PATH', 'instance/myp.db')
 app.config['SESSION_COOKIE_HTTPONLY'] = True
 app.config['SESSION_COOKIE_SECURE'] = os.environ.get('FLASK_ENV') == 'production'
 app.config['SESSION_COOKIE_SAMESITE'] = 'Lax'
@@ -52,28 +49,144 @@ app.logger.addHandler(file_handler)
 app.logger.setLevel(logging.INFO)
 app.logger.info('MYP Backend starting up')
 
-# DB Setup
-db = SQLAlchemy(app)
-migrate = Migrate(app, db)
+# Database functions
+def get_db():
+    if 'db' not in g:
+        # Stelle sicher, dass das instance-Verzeichnis existiert
+        os.makedirs(os.path.dirname(app.config['DATABASE']), exist_ok=True)
+        g.db = sqlite3.connect(app.config['DATABASE'])
+        g.db.row_factory = sqlite3.Row
+    return g.db
 
-# Lokale Authentifizierung statt OAuth
+def close_db(e=None):
+    db = g.pop('db', None)
+    if db is not None:
+        db.close()
 
-# Models
-class User(db.Model):
-    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
-    username = db.Column(db.String(64), index=True, unique=True)
-    password_hash = db.Column(db.String(128))
-    display_name = db.Column(db.String(100))
-    email = db.Column(db.String(120), index=True, unique=True)
-    role = db.Column(db.String(20), default='user')  # admin, user, guest
-    jobs = db.relationship('PrintJob', backref='user', lazy='dynamic')
+def init_db():
+    """Initialisiere die Datenbank, falls sie noch nicht existiert."""
+    db = get_db()
+    db.execute('PRAGMA foreign_keys = ON')  # SQLite-Fremdschlüsselunterstützung aktivieren
+    
+    # Tabellen erstellen
+    db.executescript('''
+    CREATE TABLE IF NOT EXISTS user (
+        id TEXT PRIMARY KEY,
+        username TEXT UNIQUE NOT NULL,
+        password_hash TEXT NOT NULL,
+        display_name TEXT,
+        email TEXT UNIQUE,
+        role TEXT DEFAULT 'user'
+    );
+    
+    CREATE TABLE IF NOT EXISTS session (
+        id TEXT PRIMARY KEY,
+        user_id TEXT NOT NULL,
+        expires_at TIMESTAMP NOT NULL,
+        FOREIGN KEY (user_id) REFERENCES user (id) ON DELETE CASCADE
+    );
+    
+    CREATE TABLE IF NOT EXISTS printer (
+        id TEXT PRIMARY KEY,
+        name TEXT NOT NULL,
+        description TEXT NOT NULL,
+        status INTEGER DEFAULT 0,
+        ip_address TEXT
+    );
+    
+    CREATE TABLE IF NOT EXISTS print_job (
+        id TEXT PRIMARY KEY,
+        printer_id TEXT NOT NULL,
+        user_id TEXT NOT NULL,
+        start_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        duration_in_minutes INTEGER NOT NULL,
+        comments TEXT,
+        aborted INTEGER DEFAULT 0,
+        abort_reason TEXT,
+        FOREIGN KEY (printer_id) REFERENCES printer (id) ON DELETE CASCADE,
+        FOREIGN KEY (user_id) REFERENCES user (id) ON DELETE CASCADE
+    );
+    ''')
+    
+    db.commit()
+
+# Initialisiere die Datenbank beim Starten der Anwendung
+with app.app_context():
+    init_db()
+
+app.teardown_appcontext(close_db)
+
+class User:
+    @staticmethod
+    def get_by_id(user_id):
+        db = get_db()
+        row = db.execute('SELECT * FROM user WHERE id = ?', (user_id,)).fetchone()
+        if row:
+            return User.from_row(row)
+        return None
+    
+    @staticmethod
+    def get_by_username(username):
+        db = get_db()
+        row = db.execute('SELECT * FROM user WHERE username = ?', (username,)).fetchone()
+        if row:
+            return User.from_row(row)
+        return None
+    
+    @staticmethod
+    def get_all():
+        db = get_db()
+        rows = db.execute('SELECT * FROM user').fetchall()
+        return [User.from_row(row) for row in rows]
+    
+    @staticmethod
+    def from_row(row):
+        user = User()
+        user.id = row['id']
+        user.username = row['username']
+        user.password_hash = row['password_hash']
+        user.display_name = row['display_name']
+        user.email = row['email']
+        user.role = row['role']
+        return user
+    
+    def __init__(self, **kwargs):
+        self.id = kwargs.get('id', str(uuid.uuid4()))
+        self.username = kwargs.get('username')
+        self.password_hash = kwargs.get('password_hash')
+        self.display_name = kwargs.get('display_name')
+        self.email = kwargs.get('email')
+        self.role = kwargs.get('role', 'user')
     
     def set_password(self, password):
         self.password_hash = generate_password_hash(password)
-        
+    
     def check_password(self, password):
         return check_password_hash(self.password_hash, password)
     
+    def save(self):
+        db = get_db()
+        db.execute(
+            'INSERT INTO user (id, username, password_hash, display_name, email, role) VALUES (?, ?, ?, ?, ?, ?)',
+            (self.id, self.username, self.password_hash, self.display_name, self.email, self.role)
+        )
+        db.commit()
+        return self
+    
+    def update(self):
+        db = get_db()
+        db.execute(
+            'UPDATE user SET username = ?, password_hash = ?, display_name = ?, email = ?, role = ? WHERE id = ?',
+            (self.username, self.password_hash, self.display_name, self.email, self.role, self.id)
+        )
+        db.commit()
+        return self
+    
+    def delete(self):
+        db = get_db()
+        db.execute('DELETE FROM user WHERE id = ?', (self.id,))
+        db.commit()
+    
     def to_dict(self):
         return {
             'id': self.id,
@@ -83,22 +196,119 @@ class User(db.Model):
             'role': self.role
         }
 
-class Session(db.Model):
-    id = db.Column(db.String(36), primary_key=True)
-    user_id = db.Column(db.String(36), db.ForeignKey('user.id'), nullable=False)
-    expires_at = db.Column(db.DateTime, nullable=False)
-    user = db.relationship('User', backref=db.backref('sessions', lazy=True))
+class Session:
+    @staticmethod
+    def get_by_id(session_id):
+        db = get_db()
+        row = db.execute('SELECT * FROM session WHERE id = ?', (session_id,)).fetchone()
+        if row:
+            return Session.from_row(row)
+        return None
+    
+    @staticmethod
+    def delete_by_user_id(user_id):
+        db = get_db()
+        db.execute('DELETE FROM session WHERE user_id = ?', (user_id,))
+        db.commit()
+    
+    @staticmethod
+    def from_row(row):
+        session = Session()
+        session.id = row['id']
+        session.user_id = row['user_id']
+        session.expires_at = datetime.datetime.fromisoformat(row['expires_at'])
+        return session
+    
+    def __init__(self, **kwargs):
+        self.id = kwargs.get('id', str(uuid.uuid4()))
+        self.user_id = kwargs.get('user_id')
+        self.expires_at = kwargs.get('expires_at')
+    
+    def save(self):
+        db = get_db()
+        db.execute(
+            'INSERT INTO session (id, user_id, expires_at) VALUES (?, ?, ?)',
+            (self.id, self.user_id, self.expires_at.isoformat())
+        )
+        db.commit()
+        return self
+    
+    def delete(self):
+        db = get_db()
+        db.execute('DELETE FROM session WHERE id = ?', (self.id,))
+        db.commit()
+    
+    @property
+    def user(self):
+        return User.get_by_id(self.user_id)
 
-class Printer(db.Model):
-    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
-    name = db.Column(db.String(64), index=True, nullable=False)
-    description = db.Column(db.Text, nullable=False)
-    status = db.Column(db.Integer, default=0)  # 0=available, 1=busy, 2=maintenance
-    ip_address = db.Column(db.String(15), nullable=True)  # IP-Adresse der Tapo-Steckdose
-    jobs = db.relationship('PrintJob', backref='printer', lazy='dynamic')
+class Printer:
+    @staticmethod
+    def get_by_id(printer_id):
+        db = get_db()
+        row = db.execute('SELECT * FROM printer WHERE id = ?', (printer_id,)).fetchone()
+        if row:
+            return Printer.from_row(row)
+        return None
+    
+    @staticmethod
+    def get_all():
+        db = get_db()
+        rows = db.execute('SELECT * FROM printer').fetchall()
+        return [Printer.from_row(row) for row in rows]
+    
+    @staticmethod
+    def from_row(row):
+        printer = Printer()
+        printer.id = row['id']
+        printer.name = row['name']
+        printer.description = row['description']
+        printer.status = row['status']
+        printer.ip_address = row['ip_address']
+        return printer
+    
+    def __init__(self, **kwargs):
+        self.id = kwargs.get('id', str(uuid.uuid4()))
+        self.name = kwargs.get('name')
+        self.description = kwargs.get('description')
+        self.status = kwargs.get('status', 0)
+        self.ip_address = kwargs.get('ip_address')
+    
+    def save(self):
+        db = get_db()
+        db.execute(
+            'INSERT INTO printer (id, name, description, status, ip_address) VALUES (?, ?, ?, ?, ?)',
+            (self.id, self.name, self.description, self.status, self.ip_address)
+        )
+        db.commit()
+        return self
+    
+    def update(self):
+        db = get_db()
+        db.execute(
+            'UPDATE printer SET name = ?, description = ?, status = ?, ip_address = ? WHERE id = ?',
+            (self.name, self.description, self.status, self.ip_address, self.id)
+        )
+        db.commit()
+        return self
+    
+    def delete(self):
+        db = get_db()
+        db.execute('DELETE FROM printer WHERE id = ?', (self.id,))
+        db.commit()
     
     def get_latest_job(self):
-        return PrintJob.query.filter_by(printer_id=self.id).order_by(PrintJob.start_at.desc()).first()
+        db = get_db()
+        row = db.execute('''
+            SELECT * FROM print_job
+            WHERE printer_id = ?
+            ORDER BY start_at DESC
+            LIMIT 1
+        ''', (self.id,)).fetchone()
+        
+        if row:
+            return PrintJob.from_row(row)
+        return None
     
     def to_dict(self):
         latest_job = self.get_latest_job()
@@ -110,15 +320,90 @@ class Printer(db.Model):
             'latestJob': latest_job.to_dict() if latest_job else None
         }
 
-class PrintJob(db.Model):
-    id = db.Column(db.String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
-    printer_id = db.Column(db.String(36), db.ForeignKey('printer.id'), nullable=False)
-    user_id = db.Column(db.String(36), db.ForeignKey('user.id'), nullable=False)
-    start_at = db.Column(db.DateTime, default=datetime.datetime.utcnow)
-    duration_in_minutes = db.Column(db.Integer, nullable=False)
-    comments = db.Column(db.Text, nullable=True)
-    aborted = db.Column(db.Boolean, default=False)
-    abort_reason = db.Column(db.Text, nullable=True)
+class PrintJob:
+    @staticmethod
+    def get_by_id(job_id):
+        db = get_db()
+        row = db.execute('SELECT * FROM print_job WHERE id = ?', (job_id,)).fetchone()
+        if row:
+            return PrintJob.from_row(row)
+        return None
+    
+    @staticmethod
+    def get_by_user_id(user_id):
+        db = get_db()
+        rows = db.execute('SELECT * FROM print_job WHERE user_id = ?', (user_id,)).fetchall()
+        return [PrintJob.from_row(row) for row in rows]
+    
+    @staticmethod
+    def get_all():
+        db = get_db()
+        rows = db.execute('SELECT * FROM print_job').fetchall()
+        return [PrintJob.from_row(row) for row in rows]
+    
+    @staticmethod
+    def get_expired_jobs():
+        db = get_db()
+        now = datetime.datetime.utcnow().isoformat()
+        rows = db.execute('''
+            SELECT * FROM print_job
+            WHERE aborted = 0
+            AND datetime(start_at, '+' || duration_in_minutes || ' minutes') <= datetime(?)
+        ''', (now,)).fetchall()
+        return [PrintJob.from_row(row) for row in rows]
+    
+    @staticmethod
+    def from_row(row):
+        job = PrintJob()
+        job.id = row['id']
+        job.printer_id = row['printer_id']
+        job.user_id = row['user_id']
+        job.start_at = datetime.datetime.fromisoformat(row['start_at'])
+        job.duration_in_minutes = row['duration_in_minutes']
+        job.comments = row['comments']
+        job.aborted = bool(row['aborted'])
+        job.abort_reason = row['abort_reason']
+        return job
+    
+    def __init__(self, **kwargs):
+        self.id = kwargs.get('id', str(uuid.uuid4()))
+        self.printer_id = kwargs.get('printer_id')
+        self.user_id = kwargs.get('user_id')
+        self.start_at = kwargs.get('start_at', datetime.datetime.utcnow())
+        self.duration_in_minutes = kwargs.get('duration_in_minutes')
+        self.comments = kwargs.get('comments')
+        self.aborted = kwargs.get('aborted', False)
+        self.abort_reason = kwargs.get('abort_reason')
+    
+    def save(self):
+        db = get_db()
+        db.execute(
+            '''INSERT INTO print_job 
+               (id, printer_id, user_id, start_at, duration_in_minutes, comments, aborted, abort_reason)
+               VALUES (?, ?, ?, ?, ?, ?, ?, ?)''',
+            (self.id, self.printer_id, self.user_id, self.start_at.isoformat(), 
+             self.duration_in_minutes, self.comments, int(self.aborted), self.abort_reason)
+        )
+        db.commit()
+        return self
+    
+    def update(self):
+        db = get_db()
+        db.execute(
+            '''UPDATE print_job SET 
+               printer_id = ?, user_id = ?, start_at = ?, duration_in_minutes = ?,
+               comments = ?, aborted = ?, abort_reason = ? 
+               WHERE id = ?''',
+            (self.printer_id, self.user_id, self.start_at.isoformat(), self.duration_in_minutes,
+             self.comments, int(self.aborted), self.abort_reason, self.id)
+        )
+        db.commit()
+        return self
+    
+    def delete(self):
+        db = get_db()
+        db.execute('DELETE FROM print_job WHERE id = ?', (self.id,))
+        db.commit()
     
     @property
     def end_at(self):
@@ -198,11 +483,10 @@ def get_current_user():
     if not session_id:
         return None
     
-    session = Session.query.get(session_id)
+    session = Session.get_by_id(session_id)
     if not session or session.expires_at < datetime.datetime.utcnow():
         if session:
-            db.session.delete(session)
-            db.session.commit()
+            session.delete()
         flask_session.pop('session_id', None)
         return None
     
@@ -234,8 +518,7 @@ def create_session(user):
     expires_at = datetime.datetime.utcnow() + timedelta(days=7)
     
     session = Session(id=session_id, user_id=user.id, expires_at=expires_at)
-    db.session.add(session)
-    db.session.commit()
+    session.save()
     
     flask_session['session_id'] = session_id
     flask_session.permanent = True
@@ -255,14 +538,12 @@ def register():
     display_name = data.get('displayName', username)
     email = data.get('email', '')
     
-    if User.query.filter_by(username=username).first():
+    if User.get_by_username(username):
         return jsonify({'message': 'Benutzername bereits vergeben!'}), 400
     
-    if email and User.query.filter_by(email=email).first():
-        return jsonify({'message': 'E-Mail-Adresse bereits registriert!'}), 400
-    
     # Prüfen, ob es bereits einen Admin gibt
-    admin_exists = User.query.filter_by(role='admin').first() is not None
+    db = get_db()
+    admin_exists = db.execute("SELECT 1 FROM user WHERE role = 'admin' LIMIT 1").fetchone() is not None
     
     # Falls kein Admin existiert, wird der erste Benutzer zum Admin
     role = 'admin' if not admin_exists else 'user'
@@ -274,9 +555,8 @@ def register():
         role=role
     )
     user.set_password(password)
+    user.save()
     
-    db.session.add(user)
-    db.session.commit()
     app.logger.info(f'Neuer Benutzer registriert: {username} (Rolle: {role})')
     
     # Session erstellen
@@ -297,7 +577,7 @@ def login():
     username = data.get('username')
     password = data.get('password')
     
-    user = User.query.filter_by(username=username).first()
+    user = User.get_by_username(username)
     
     if not user or not user.check_password(password):
         return jsonify({'message': 'Ungültiger Benutzername oder Passwort!'}), 401
@@ -314,10 +594,9 @@ def login():
 def logout():
     session_id = flask_session.get('session_id')
     if session_id:
-        session = Session.query.get(session_id)
+        session = Session.get_by_id(session_id)
         if session:
-            db.session.delete(session)
-            db.session.commit()
+            session.delete()
         
         flask_session.pop('session_id', None)
     
@@ -337,7 +616,7 @@ def get_me():
 
 @app.route('/api/printers', methods=['GET'])
 def get_printers():
-    printers = Printer.query.all()
+    printers = Printer.get_all()
     return jsonify([printer.to_dict() for printer in printers])
 
 @app.route('/api/printers', methods=['POST'])
@@ -356,21 +635,25 @@ def create_printer():
         ip_address=data.get('ipAddress')
     )
     
-    db.session.add(printer)
-    db.session.commit()
+    printer.save()
     
     return jsonify(printer.to_dict()), 201
 
 @app.route('/api/printers/<printer_id>', methods=['GET'])
 def get_printer(printer_id):
-    printer = Printer.query.get_or_404(printer_id)
+    printer = Printer.get_by_id(printer_id)
+    if not printer:
+        return jsonify({'message': 'Drucker nicht gefunden!'}), 404
     return jsonify(printer.to_dict())
 
 @app.route('/api/printers/<printer_id>', methods=['PUT'])
 @login_required
 @admin_required
 def update_printer(printer_id):
-    printer = Printer.query.get_or_404(printer_id)
+    printer = Printer.get_by_id(printer_id)
+    if not printer:
+        return jsonify({'message': 'Drucker nicht gefunden!'}), 404
+        
     data = request.get_json()
     
     if data.get('name'):
@@ -382,16 +665,18 @@ def update_printer(printer_id):
     if data.get('ipAddress'):
         printer.ip_address = data['ipAddress']
     
-    db.session.commit()
+    printer.update()
     return jsonify(printer.to_dict())
 
 @app.route('/api/printers/<printer_id>', methods=['DELETE'])
 @login_required
 @admin_required
 def delete_printer(printer_id):
-    printer = Printer.query.get_or_404(printer_id)
-    db.session.delete(printer)
-    db.session.commit()
+    printer = Printer.get_by_id(printer_id)
+    if not printer:
+        return jsonify({'message': 'Drucker nicht gefunden!'}), 404
+        
+    printer.delete()
     return jsonify({'message': 'Drucker gelöscht!'})
 
 @app.route('/api/jobs', methods=['GET'])
@@ -399,9 +684,9 @@ def delete_printer(printer_id):
 def get_jobs():
     # Admins sehen alle Jobs, normale Benutzer nur ihre eigenen
     if g.current_user.role == 'admin':
-        jobs = PrintJob.query.all()
+        jobs = PrintJob.get_all()
     else:
-        jobs = PrintJob.query.filter_by(user_id=g.current_user.id).all()
+        jobs = PrintJob.get_by_user_id(g.current_user.id)
     
     return jsonify([job.to_dict() for job in jobs])
 
@@ -413,7 +698,9 @@ def create_job():
     if not data or not data.get('printerId') or not data.get('durationInMinutes'):
         return jsonify({'message': 'Drucker-ID und Dauer sind erforderlich!'}), 400
     
-    printer = Printer.query.get_or_404(data['printerId'])
+    printer = Printer.get_by_id(data['printerId'])
+    if not printer:
+        return jsonify({'message': 'Drucker nicht gefunden!'}), 404
     
     if printer.status != 0:  # 0 = available
         return jsonify({'message': 'Drucker ist nicht verfügbar!'}), 400
@@ -429,9 +716,9 @@ def create_job():
     
     # Drucker als belegt markieren
     printer.status = 1  # 1 = busy
+    printer.update()
     
-    db.session.add(job)
-    db.session.commit()
+    job.save()
     
     # Steckdose einschalten, falls IP-Adresse hinterlegt ist
     if printer.ip_address:
@@ -446,10 +733,12 @@ def create_job():
 @login_required
 def get_job(job_id):
     # Admins können alle Jobs sehen, Benutzer nur ihre eigenen
-    if g.current_user.role == 'admin':
-        job = PrintJob.query.get_or_404(job_id)
-    else:
-        job = PrintJob.query.filter_by(id=job_id, user_id=g.current_user.id).first_or_404()
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
+        
+    if g.current_user.role != 'admin' and job.user_id != g.current_user.id:
+        return jsonify({'message': 'Keine Berechtigung für diesen Job!'}), 403
     
     return jsonify(job.to_dict())
 
@@ -457,24 +746,27 @@ def get_job(job_id):
 @login_required
 def abort_job(job_id):
     # Admins können alle Jobs abbrechen, Benutzer nur ihre eigenen
-    if g.current_user.role == 'admin':
-        job = PrintJob.query.get_or_404(job_id)
-    else:
-        job = PrintJob.query.filter_by(id=job_id, user_id=g.current_user.id).first_or_404()
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
+        
+    if g.current_user.role != 'admin' and job.user_id != g.current_user.id:
+        return jsonify({'message': 'Keine Berechtigung für diesen Job!'}), 403
     
     data = request.get_json()
     
     job.aborted = True
     job.abort_reason = data.get('reason', '')
+    job.update()
     
     # Drucker wieder verfügbar machen
-    printer = job.printer
-    printer.status = 0  # 0 = available
-    
-    db.session.commit()
+    printer = Printer.get_by_id(job.printer_id)
+    if printer:
+        printer.status = 0  # 0 = available
+        printer.update()
     
     # Steckdose ausschalten, falls IP-Adresse hinterlegt ist
-    if printer.ip_address:
+    if printer and printer.ip_address:
         try:
             asyncio.run(tapo_control.turn_off(printer.ip_address))
         except Exception as e:
@@ -486,24 +778,27 @@ def abort_job(job_id):
 @login_required
 def finish_job(job_id):
     # Admins können alle Jobs beenden, Benutzer nur ihre eigenen
-    if g.current_user.role == 'admin':
-        job = PrintJob.query.get_or_404(job_id)
-    else:
-        job = PrintJob.query.filter_by(id=job_id, user_id=g.current_user.id).first_or_404()
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
+        
+    if g.current_user.role != 'admin' and job.user_id != g.current_user.id:
+        return jsonify({'message': 'Keine Berechtigung für diesen Job!'}), 403
     
     # Aktuelle Zeit als Ende setzen
     now = datetime.datetime.utcnow()
     actual_duration = int((now - job.start_at).total_seconds() / 60)
     job.duration_in_minutes = actual_duration
+    job.update()
     
     # Drucker wieder verfügbar machen
-    printer = job.printer
-    printer.status = 0  # 0 = available
-    
-    db.session.commit()
+    printer = Printer.get_by_id(job.printer_id)
+    if printer:
+        printer.status = 0  # 0 = available
+        printer.update()
     
     # Steckdose ausschalten, falls IP-Adresse hinterlegt ist
-    if printer.ip_address:
+    if printer and printer.ip_address:
         try:
             asyncio.run(tapo_control.turn_off(printer.ip_address))
         except Exception as e:
@@ -515,10 +810,12 @@ def finish_job(job_id):
 @login_required
 def extend_job(job_id):
     # Admins können alle Jobs verlängern, Benutzer nur ihre eigenen
-    if g.current_user.role == 'admin':
-        job = PrintJob.query.get_or_404(job_id)
-    else:
-        job = PrintJob.query.filter_by(id=job_id, user_id=g.current_user.id).first_or_404()
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
+        
+    if g.current_user.role != 'admin' and job.user_id != g.current_user.id:
+        return jsonify({'message': 'Keine Berechtigung für diesen Job!'}), 403
     
     data = request.get_json()
     minutes = int(data.get('minutes', 0))
@@ -529,8 +826,7 @@ def extend_job(job_id):
         return jsonify({'message': 'Ungültige Verlängerungszeit!'}), 400
     
     job.duration_in_minutes += additional_minutes
-    
-    db.session.commit()
+    job.update()
     
     return jsonify(job.to_dict())
 
@@ -538,21 +834,24 @@ def extend_job(job_id):
 @login_required
 def update_job_comments(job_id):
     # Admins können alle Jobs bearbeiten, Benutzer nur ihre eigenen
-    if g.current_user.role == 'admin':
-        job = PrintJob.query.get_or_404(job_id)
-    else:
-        job = PrintJob.query.filter_by(id=job_id, user_id=g.current_user.id).first_or_404()
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
+        
+    if g.current_user.role != 'admin' and job.user_id != g.current_user.id:
+        return jsonify({'message': 'Keine Berechtigung für diesen Job!'}), 403
     
     data = request.get_json()
     job.comments = data.get('comments', '')
-    
-    db.session.commit()
+    job.update()
     
     return jsonify(job.to_dict())
 
 @app.route('/api/job/<job_id>/remaining-time', methods=['GET'])
 def job_remaining_time(job_id):
-    job = PrintJob.query.get_or_404(job_id)
+    job = PrintJob.get_by_id(job_id)
+    if not job:
+        return jsonify({'message': 'Job nicht gefunden!'}), 404
     
     remaining = job.remaining_time()
     return jsonify({'remaining_minutes': remaining})
@@ -561,21 +860,26 @@ def job_remaining_time(job_id):
 @login_required
 @admin_required
 def get_users():
-    users = User.query.all()
+    users = User.get_all()
     return jsonify([user.to_dict() for user in users])
 
 @app.route('/api/users/<user_id>', methods=['GET'])
 @login_required
 @admin_required
 def get_user(user_id):
-    user = User.query.get_or_404(user_id)
+    user = User.get_by_id(user_id)
+    if not user:
+        return jsonify({'message': 'Benutzer nicht gefunden!'}), 404
     return jsonify(user.to_dict())
 
 @app.route('/api/users/<user_id>', methods=['PUT'])
 @login_required
 @admin_required
 def update_user(user_id):
-    user = User.query.get_or_404(user_id)
+    user = User.get_by_id(user_id)
+    if not user:
+        return jsonify({'message': 'Benutzer nicht gefunden!'}), 404
+        
     data = request.get_json()
     
     if data.get('username'):
@@ -587,47 +891,55 @@ def update_user(user_id):
     if data.get('role'):
         user.role = data['role']
     
-    db.session.commit()
+    user.update()
     return jsonify(user.to_dict())
 
 @app.route('/api/users/<user_id>', methods=['DELETE'])
 @login_required
 @admin_required
 def delete_user(user_id):
-    user = User.query.get_or_404(user_id)
+    user = User.get_by_id(user_id)
+    if not user:
+        return jsonify({'message': 'Benutzer nicht gefunden!'}), 404
     
     # Löschen aller Sessions des Benutzers
-    Session.query.filter_by(user_id=user.id).delete()
+    Session.delete_by_user_id(user.id)
     
-    db.session.delete(user)
-    db.session.commit()
+    user.delete()
     return jsonify({'message': 'Benutzer gelöscht!'})
 
 @app.route('/api/stats', methods=['GET'])
 @login_required
 @admin_required
 def stats():
+    db = get_db()
+    
     # Drucker-Nutzungsstatistiken
-    total_printers = Printer.query.count()
-    available_printers = Printer.query.filter_by(status=0).count()
+    total_printers = db.execute('SELECT COUNT(*) as count FROM printer').fetchone()['count']
+    available_printers = db.execute('SELECT COUNT(*) as count FROM printer WHERE status = 0').fetchone()['count']
     
     # Job-Statistiken
-    total_jobs = PrintJob.query.count()
-    active_jobs = PrintJob.query.filter(
-        PrintJob.aborted == False,
-        PrintJob.start_at + timedelta(minutes=PrintJob.duration_in_minutes) > datetime.datetime.utcnow()
-    ).count()
-    completed_jobs = PrintJob.query.filter(
-        PrintJob.aborted == False,
-        PrintJob.start_at + timedelta(minutes=PrintJob.duration_in_minutes) <= datetime.datetime.utcnow()
-    ).count()
+    total_jobs = db.execute('SELECT COUNT(*) as count FROM print_job').fetchone()['count']
+    
+    now = datetime.datetime.utcnow().isoformat()
+    active_jobs = db.execute('''
+        SELECT COUNT(*) as count FROM print_job
+        WHERE aborted = 0
+        AND datetime(start_at, '+' || duration_in_minutes || ' minutes') > datetime(?)
+    ''', (now,)).fetchone()['count']
+    
+    completed_jobs = db.execute('''
+        SELECT COUNT(*) as count FROM print_job
+        WHERE aborted = 0
+        AND datetime(start_at, '+' || duration_in_minutes || ' minutes') <= datetime(?)
+    ''', (now,)).fetchone()['count']
     
     # Benutzerstatistiken
-    total_users = User.query.count()
+    total_users = db.execute('SELECT COUNT(*) as count FROM user').fetchone()['count']
     
     # Durchschnittliche Druckdauer
-    avg_duration_result = db.session.query(db.func.avg(PrintJob.duration_in_minutes)).first()
-    avg_duration = int(avg_duration_result[0]) if avg_duration_result[0] else 0
+    avg_duration_result = db.execute('SELECT AVG(duration_in_minutes) as avg FROM print_job').fetchone()
+    avg_duration = int(avg_duration_result['avg']) if avg_duration_result['avg'] else 0
     
     return jsonify({
         'printers': {
@@ -650,32 +962,26 @@ def stats():
 @app.cli.command("check-jobs")
 def check_jobs():
     """Überprüft abgelaufene Jobs und schaltet Steckdosen aus."""
-    now = datetime.datetime.utcnow()
-    
-    # Abgelaufene Jobs finden
-    expired_jobs = PrintJob.query.filter(
-        PrintJob.aborted == False,
-        PrintJob.start_at + timedelta(minutes=PrintJob.duration_in_minutes) <= now
-    ).all()
-    
-    for job in expired_jobs:
-        printer = job.printer
+    with app.app_context():
+        expired_jobs = PrintJob.get_expired_jobs()
         
-        # Drucker-Status auf verfügbar setzen
-        if printer.status == 1:  # busy
-            printer.status = 0  # available
-            app.logger.info(f"Job {job.id} abgelaufen. Drucker {printer.id} auf verfügbar gesetzt.")
+        for job in expired_jobs:
+            printer = Printer.get_by_id(job.printer_id)
+            
+            if printer and printer.status == 1:  # busy
+                printer.status = 0  # available
+                printer.update()
+                app.logger.info(f"Job {job.id} abgelaufen. Drucker {printer.id} auf verfügbar gesetzt.")
+            
+            # Steckdose ausschalten, falls IP-Adresse hinterlegt ist
+            if printer and printer.ip_address:
+                try:
+                    asyncio.run(tapo_control.turn_off(printer.ip_address))
+                    app.logger.info(f"Steckdose {printer.ip_address} für abgelaufenen Job {job.id} ausgeschaltet.")
+                except Exception as e:
+                    app.logger.error(f"Fehler beim Ausschalten der Steckdose {printer.ip_address}: {e}")
         
-        # Steckdose ausschalten, falls IP-Adresse hinterlegt ist
-        if printer.ip_address:
-            try:
-                asyncio.run(tapo_control.turn_off(printer.ip_address))
-                app.logger.info(f"Steckdose {printer.ip_address} für abgelaufenen Job {job.id} ausgeschaltet.")
-            except Exception as e:
-                app.logger.error(f"Fehler beim Ausschalten der Steckdose {printer.ip_address}: {e}")
-    
-    db.session.commit()
-    app.logger.info(f"{len(expired_jobs)} abgelaufene Jobs überprüft und Steckdosen aktualisiert.")
+        app.logger.info(f"{len(expired_jobs)} abgelaufene Jobs überprüft und Steckdosen aktualisiert.")
 
 @app.route('/api/test', methods=['GET'])
 def test():
@@ -683,7 +989,8 @@ def test():
 
 @app.route('/api/create-initial-admin', methods=['POST'])
 def create_initial_admin():
-    admin_exists = User.query.filter_by(role='admin').first() is not None
+    db = get_db()
+    admin_exists = db.execute("SELECT 1 FROM user WHERE role = 'admin' LIMIT 1").fetchone() is not None
     
     if admin_exists:
         return jsonify({'message': 'Es existiert bereits ein Administrator!'}), 400
@@ -705,9 +1012,8 @@ def create_initial_admin():
         role='admin'
     )
     user.set_password(password)
+    user.save()
     
-    db.session.add(user)
-    db.session.commit()
     app.logger.info(f'Initialer Admin-Benutzer erstellt: {username}')
     
     return jsonify({
@@ -745,10 +1051,9 @@ def register_page():
 def logout_page():
     session_id = flask_session.get('session_id')
     if session_id:
-        session = Session.query.get(session_id)
+        session = Session.get_by_id(session_id)
         if session:
-            db.session.delete(session)
-            db.session.commit()
+            session.delete()
         
         flask_session.pop('session_id', None)
     
diff --git a/backend/initialize_myp_database.sh b/backend/initialize_myp_database.sh
index e1895a1..73005ba 100755
--- a/backend/initialize_myp_database.sh
+++ b/backend/initialize_myp_database.sh
@@ -6,16 +6,10 @@
 echo "=== MYP Datenbank Initialisierung ==="
 echo ""
 
-# Aktiviere virtuelle Umgebung, falls vorhanden
-if [ -d "venv" ]; then
-    echo "Aktiviere virtuelle Python-Umgebung..."
-    source venv/bin/activate
-fi
-
-# Prüfe, ob Flask installiert ist
-if ! python -c "import flask" &> /dev/null; then
-    echo "FEHLER: Flask ist nicht installiert."
-    echo "Bitte führe zuerst 'pip install -r requirements.txt' aus."
+# Prüfe, ob sqlite3 installiert ist
+if ! command -v sqlite3 &> /dev/null; then
+    echo "FEHLER: sqlite3 ist nicht installiert."
+    echo "Bitte installiere sqlite3 mit deinem Paketmanager, z.B. 'apt install sqlite3'"
     exit 1
 fi
 
@@ -23,12 +17,58 @@ fi
 echo "Erstelle instance-Ordner, falls nicht vorhanden..."
 mkdir -p instance/backups
 
-# Initialisiere die Datenbank
-echo ""
-echo "Initialisiere die Datenbank..."
-FLASK_APP=app.py flask db init
-FLASK_APP=app.py flask db migrate -m "Initiale Datenbank-Erstellung"
-FLASK_APP=app.py flask db upgrade
+# Prüfen, ob die Datenbank bereits existiert
+if [ -f "instance/myp.db" ]; then
+    echo "Datenbank existiert bereits."
+    echo "Erstelle Backup in instance/backups..."
+    cp instance/myp.db "instance/backups/myp_$(date '+%Y%m%d_%H%M%S').db"
+fi
+
+# Erstelle die Datenbank und ihre Tabellen
+echo "Erstelle neue Datenbank..."
+sqlite3 instance/myp.db <<EOF
+PRAGMA foreign_keys = ON;
+
+CREATE TABLE IF NOT EXISTS user (
+    id TEXT PRIMARY KEY,
+    username TEXT UNIQUE NOT NULL,
+    password_hash TEXT NOT NULL,
+    display_name TEXT,
+    email TEXT UNIQUE,
+    role TEXT DEFAULT 'user'
+);
+
+CREATE TABLE IF NOT EXISTS session (
+    id TEXT PRIMARY KEY,
+    user_id TEXT NOT NULL,
+    expires_at TIMESTAMP NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES user (id) ON DELETE CASCADE
+);
+
+CREATE TABLE IF NOT EXISTS printer (
+    id TEXT PRIMARY KEY,
+    name TEXT NOT NULL,
+    description TEXT NOT NULL,
+    status INTEGER DEFAULT 0,
+    ip_address TEXT
+);
+
+CREATE TABLE IF NOT EXISTS print_job (
+    id TEXT PRIMARY KEY,
+    printer_id TEXT NOT NULL,
+    user_id TEXT NOT NULL,
+    start_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    duration_in_minutes INTEGER NOT NULL,
+    comments TEXT,
+    aborted INTEGER DEFAULT 0,
+    abort_reason TEXT,
+    FOREIGN KEY (printer_id) REFERENCES printer (id) ON DELETE CASCADE,
+    FOREIGN KEY (user_id) REFERENCES user (id) ON DELETE CASCADE
+);
+EOF
+
+# Setze Berechtigungen für die Datenbankdatei
+chmod 644 instance/myp.db
 
 echo ""
 echo "=== Datenbank-Initialisierung abgeschlossen ==="
@@ -38,4 +78,7 @@ echo "Der erste registrierte Benutzer wird automatisch zum Admin."
 echo ""
 echo "Starte den Server mit:"
 echo "python app.py"
+echo ""
+echo "Alternativ kannst du einen Admin-Benutzer über die API erstellen mit:"
+echo "curl -X POST http://localhost:5000/api/create-initial-admin -H \"Content-Type: application/json\" -d '{\"username\":\"admin\",\"password\":\"password\",\"displayName\":\"Administrator\"}'"
 echo ""
\ No newline at end of file
diff --git a/backend/install.sh b/backend/install.sh
index 8845747..ba45c73 100755
--- a/backend/install.sh
+++ b/backend/install.sh
@@ -16,6 +16,13 @@ if [[ "$(printf '%s\n' "$required_version" "$python_version" | sort -V | head -n
     exit 1
 fi
 
+# Prüfe, ob sqlite3 installiert ist
+if ! command -v sqlite3 &> /dev/null; then
+    echo "FEHLER: sqlite3 ist nicht installiert."
+    echo "Bitte installiere sqlite3 mit deinem Paketmanager, z.B. 'apt install sqlite3'"
+    exit 1
+fi
+
 # Erstelle virtuelle Umgebung
 echo ""
 echo "Erstelle virtuelle Python-Umgebung..."
@@ -34,7 +41,7 @@ echo "Erstelle .env-Datei..."
 if [ ! -f .env ]; then
     cp .env.example .env
     echo "Die .env-Datei wurde aus der Beispieldatei erstellt."
-    echo "Bitte passe die Konfiguration für GitHub OAuth und Tapo-Steckdosen an."
+    echo "Bitte passe die Konfiguration an, falls nötig."
 else
     echo ".env-Datei existiert bereits."
 fi
@@ -44,24 +51,17 @@ echo ""
 echo "Erstelle logs-Ordner..."
 mkdir -p logs
 
-# Erstelle Instance und Backup Ordner
-echo ""
-echo "Erstelle instance-Ordner..."
-mkdir -p instance/backups
-
 # Initialisiere die Datenbank
 echo ""
 echo "Initialisiere die Datenbank..."
-FLASK_APP=app.py flask db init
-FLASK_APP=app.py flask db migrate -m "Initiale Datenbank-Erstellung"
-FLASK_APP=app.py flask db upgrade
+bash initialize_myp_database.sh
 
 echo ""
 echo "=== Installation abgeschlossen ==="
 echo ""
 echo "Wichtige Schritte vor dem Start:"
-echo "1. Konfiguriere die .env-Datei mit deinen GitHub OAuth-Credentials"
-echo "2. Konfiguriere die Tapo-Steckdosen-Zugangsdaten in der .env-Datei"
+echo "1. Passe die Konfigurationen in der .env-Datei an"
+echo "2. Konfiguriere die Tapo-Steckdosen-Zugangsdaten in der .env-Datei (optional)"
 echo "3. Passe die crontab-example an und installiere den Cron-Job (optional)"
 echo ""
 echo "Starte den Server mit:"
diff --git a/backend/requirements.txt b/backend/requirements.txt
index 94ab028..c2f9977 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -1,7 +1,5 @@
 flask==2.3.3
 flask-cors==4.0.0
-flask-sqlalchemy==3.1.1
-flask-migrate==4.0.5
 pyjwt==2.8.0
 python-dotenv==1.0.0
 werkzeug==2.3.7