try

main.py

@@ -52,7 +52,7 @@ def logout():
 def index():
     page = flask.request.args.get('page', 1, type=int)
     per_page = 20
-    search_query = None
+    search_query = ""
     if flask.request.method == "POST":
         search_query = flask.request.form.get("search")
     else:
@@ -93,8 +93,10 @@ def csv_output():
 
     if moviedb_func.scrape_and_add_movie(movie_name=select_add_movie,
                                      medium_id=select_medium_id, user_id=current_user.id):
+        flash("Film erfolgreich hinzugefügt!")
         return redirect(url_for('index'))
     else:
+        flash("Film konnte nicht automatisch hinzugefügt werden. Bitte versuchen Sie die manuelle Eingabe.")
         return redirect(url_for('add_movie_manually', movie_name=select_add_movie, medium_id=select_medium_id))
 
 @app.get("/add_movie_manually")
@@ -118,9 +120,12 @@ def save_manual():
     release_year = flask.request.form["release_year"]
     genre_name = flask.request.form["genre_name"]
 
-    moviedb_func.add_manual_movie(movie_name=movie_name, medium_id=int(medium_id), director_name=director_name, release_year=int(release_year), genre_name=genre_name, user_id=current_user.id)
+    if moviedb_func.add_manual_movie(movie_name=movie_name, medium_id=int(medium_id), director_name=director_name, release_year=int(release_year), genre_name=genre_name, user_id=current_user.id):
-
+        flash("Film manuell erfolgreich hinzugefügt!")
         return redirect("/")
+    else:
+        flash("Fehler: Film konnte nicht manuell hinzugefügt werden. Möglicherweise existiert dieser Film bereits in deiner Liste.")
+        return redirect(url_for('add_movie_manually', movie_name=movie_name, medium_id=medium_id))
 
 @app.route("/delete_movie/<int:movie_id>", methods=["POST"])
 @login_required

moviedb_func.py

@@ -98,7 +98,8 @@ def create_movie_database(db_name="movie_db.db"):
         medium_id integer not null,
         release_year integer,
         user_id integer not null,
-        FOREIGN KEY (user_id) REFERENCES user (id)
+        FOREIGN KEY (user_id) REFERENCES user (id),
+        UNIQUE(titel, user_id)
     )
     """
 
@@ -271,7 +272,7 @@ def scrape_and_add_movie(movie_name: str, medium_id: int, user_id: int, db_name:
         with DBcm.UseDatabase(db_name) as db:
             db.execute(SQL_PARAM, (movie_name.lower(), genre_id,
                        regie_id, medium_id, release_year, user_id,))
-    except ProgrammingError as e:
+    except (ProgrammingError, sqlite3.IntegrityError) as e:
         print(f"Error adding movie: {e}")
         return False
     return True
@@ -289,7 +290,7 @@ def add_manual_movie(movie_name: str, medium_id: int, director_name: str, releas
         with DBcm.UseDatabase(db_name) as db:
             db.execute(SQL_PARAM, (movie_name.lower(), genre_id,
                        regie_id, medium_id, release_year, user_id,)) 
-    except ProgrammingError as e:
+    except (ProgrammingError, sqlite3.IntegrityError) as e:
         print(f"Error adding movie: {e}")
         return False
     return True

templates/base.html

@@ -29,6 +29,17 @@
         </div>
     </nav>
     <div class="container mt-4">
+        {% with messages = get_flashed_messages() %}
+            {% if messages %}
+                <div class="alert alert-info" role="alert">
+                    <ul class="flashes">
+                        {% for message in messages %}
+                            <li>{{ message }}</li>
+                        {% endfor %}
+                    </ul>
+                </div>
+            {% endif %}
+        {% endwith %}
         {% block body %}{% endblock %}
     </div>
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js" integrity="sha384-YvpcrYf0tY3lHB60NNkmXc5s9fDVZLESaAA55NDzOxhy9GkcIdslK1eN7N6jIeHz" crossorigin="anonymous"></script>