Lagerorte per 10-Zeichen-Code statt fortlaufender ID; iOS-Einlagern ohne Kamerazwang

Lagerort-IDs sind jetzt ein zufaelliger 10-Zeichen-Code (wie die Einzelstueck-UIDs) statt einer fortlaufenden Zahl - so kollidiert die Stammdaten-Sicherung zwischen zwei Instanzen praktisch nie mehr, und der Code ist zugleich der Inhalt des QR /l/<code>. Alle Fremdschluessel (lots, movements, items, Mindestbestaende, parent_id) ziehen mit; die Umstellung laeuft einmalig und transaktional beim Serverstart (_migrate_locations_to_code) und rollt bei Fehlern komplett zurueck. Vor dem Deploy ein DB-Backup machen. iOS-Einlagern oeffnet nicht mehr sofort die Kamera, sondern ein Formular mit Artikelsuche; die Kamera kommt erst per Button. Im Formular laesst sich der Lagerort zusaetzlich per /l/-QR scannen. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-27 12:15:25 +02:00
parent 6e48cd0a7a
commit d518b4aa23
23 changed files with 507 additions and 220 deletions
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -39,6 +39,95 @@ from .services.group_codes import backfill as backfill_group_codes
 settings = get_settings()


+def _migrate_locations_to_code(conn) -> None:
+    """Einmalige Umstellung: Lagerort-ID von fortlaufender Zahl auf 10-Zeichen-Code.
+
+    Läuft nur, solange ``locations.id`` noch eine Integer-Spalte ist – danach ist
+    die Umstellung erledigt und der Block überspringt sich selbst. Alles passiert
+    innerhalb der umgebenden Transaktion: Bricht ein Schritt ab, wird komplett
+    zurückgerollt und die Datenbank bleibt auf dem alten (funktionierenden) Stand.
+    """
+    id_type = conn.execute(text(
+        "SELECT data_type FROM information_schema.columns "
+        "WHERE table_name = 'locations' AND column_name = 'id'"
+    )).scalar()
+    if id_type not in ("integer", "bigint", "smallint"):
+        return  # frische Installation (schon VARCHAR) oder bereits umgestellt
+
+    from .models import generate_location_code
+
+    # 1. Jedem bestehenden Lagerort einen eindeutigen Code geben (id bleibt vorerst).
+    conn.execute(text("ALTER TABLE locations ADD COLUMN IF NOT EXISTS code VARCHAR(10)"))
+    vergeben: set[str] = set()
+    for (lid,) in conn.execute(text("SELECT id FROM locations")).all():
+        code = generate_location_code()
+        while code in vergeben:
+            code = generate_location_code()
+        vergeben.add(code)
+        conn.execute(text("UPDATE locations SET code = :c WHERE id = :i"), {"c": code, "i": lid})
+
+    # 2. Fremdschlüssel-Spalten (Integer) auf den Code umziehen. Beim DROP COLUMN
+    #    fallen die alten FK-/Unique-Constraints automatisch mit weg.
+    kinder = [
+        # (Tabelle, ON DELETE, NOT NULL danach, Unique-Constraint danach)
+        ("lots", "SET NULL", False, None),
+        ("movements", "SET NULL", False, None),
+        ("items", "SET NULL", False, None),
+        ("product_location_min_stock", "CASCADE", True, ("uq_prod_loc_min", "product_id")),
+        ("group_location_min_stock", "CASCADE", True, ("uq_group_loc_min", "group_id")),
+    ]
+    vorhanden = []
+    for tabelle, ond, nn, uq in kinder:
+        spalte_da = conn.execute(text(
+            "SELECT 1 FROM information_schema.columns "
+            "WHERE table_name = :t AND column_name = 'location_id'"
+        ), {"t": tabelle}).scalar()
+        if spalte_da is None:
+            continue  # Spalte existiert (noch) nicht – nichts umzuziehen
+        vorhanden.append((tabelle, ond, nn, uq))
+        conn.execute(text(f"ALTER TABLE {tabelle} ADD COLUMN location_code VARCHAR(10)"))
+        conn.execute(text(
+            f"UPDATE {tabelle} t SET location_code = l.code "
+            f"FROM locations l WHERE t.location_id = l.id"
+        ))
+        conn.execute(text(f"ALTER TABLE {tabelle} DROP COLUMN location_id"))
+        conn.execute(text(f"ALTER TABLE {tabelle} RENAME COLUMN location_code TO location_id"))
+
+    # 2b. Selbstverweis parent_id ebenso auf den Code umziehen.
+    conn.execute(text("ALTER TABLE locations ADD COLUMN parent_code VARCHAR(10)"))
+    conn.execute(text(
+        "UPDATE locations c SET parent_code = p.code FROM locations p WHERE c.parent_id = p.id"
+    ))
+    conn.execute(text("ALTER TABLE locations DROP COLUMN parent_id"))
+
+    # 3. Integer-PK durch den Code ersetzen (DROP COLUMN zieht PK und Sequenz mit).
+    conn.execute(text("ALTER TABLE locations DROP COLUMN id"))
+    conn.execute(text("ALTER TABLE locations RENAME COLUMN code TO id"))
+    conn.execute(text("ALTER TABLE locations ALTER COLUMN id SET NOT NULL"))
+    conn.execute(text("ALTER TABLE locations ADD PRIMARY KEY (id)"))
+    conn.execute(text("ALTER TABLE locations RENAME COLUMN parent_code TO parent_id"))
+    conn.execute(text(
+        "ALTER TABLE locations ADD CONSTRAINT locations_parent_id_fkey "
+        "FOREIGN KEY (parent_id) REFERENCES locations(id) ON DELETE SET NULL"
+    ))
+
+    # 4. Fremdschlüssel (und Pflicht-/Unique-Bedingungen) neu setzen – jetzt auf den Code.
+    for tabelle, ond, nn, uq in vorhanden:
+        if nn:
+            # Verwaiste Mindestbestände (Lagerort gelöscht) vorher entfernen.
+            conn.execute(text(f"DELETE FROM {tabelle} WHERE location_id IS NULL"))
+            conn.execute(text(f"ALTER TABLE {tabelle} ALTER COLUMN location_id SET NOT NULL"))
+        conn.execute(text(
+            f"ALTER TABLE {tabelle} ADD CONSTRAINT {tabelle}_location_id_fkey "
+            f"FOREIGN KEY (location_id) REFERENCES locations(id) ON DELETE {ond}"
+        ))
+        if uq is not None:
+            name, andere = uq
+            conn.execute(text(
+                f"ALTER TABLE {tabelle} ADD CONSTRAINT {name} UNIQUE ({andere}, location_id)"
+            ))
+
+
 def _ensure_schema() -> None:
    """Schonende Migration: fehlende Spalten auf bestehenden Tabellen nachziehen.

@@ -79,7 +168,9 @@ def _ensure_schema() -> None:
        "REFERENCES shops(id) ON DELETE SET NULL",
        "ALTER TABLE products ADD COLUMN IF NOT EXISTS product_url VARCHAR(1024)",
        # Bewegungen: Lagerort (Gegenstands-Buchungen) und Entnahmegrund.
-        "ALTER TABLE movements ADD COLUMN IF NOT EXISTS location_id INTEGER "
+        # location_id ist ein Lagerort-Code (VARCHAR(10)), siehe
+        # _migrate_locations_to_code – deshalb hier gleich als VARCHAR anlegen.
+        "ALTER TABLE movements ADD COLUMN IF NOT EXISTS location_id VARCHAR(10) "
        "REFERENCES locations(id) ON DELETE SET NULL",
        "ALTER TABLE movements ADD COLUMN IF NOT EXISTS reason VARCHAR(16)",
        # Einzelstück-Verwaltung (Items mit UID/QR) je Produkt.
@@ -90,6 +181,9 @@ def _ensure_schema() -> None:
        "ALTER TABLE items ADD COLUMN IF NOT EXISTS currency VARCHAR(3)",
    ]
    with engine.begin() as conn:
+        # Zuerst die Lagerort-ID auf den Code umstellen (einmalig, idempotent),
+        # damit die folgenden ADD-COLUMN-Verweise auf die neue VARCHAR-id passen.
+        _migrate_locations_to_code(conn)
        for stmt in stmts:
            conn.execute(text(stmt))
        # Solange user_id eindeutig war, ging genau ein Dashboard je Benutzer.
--- a/backend/app/models.py
+++ b/backend/app/models.py
@@ -1,6 +1,7 @@
 from __future__ import annotations

 import enum
+import secrets
 from datetime import date, datetime, timezone

 from sqlalchemy import (
@@ -136,14 +137,28 @@ class Group(Base):
    )


+# Lagerorte tragen einen zufälligen 10-Zeichen-Code als ID statt einer
+# fortlaufenden Zahl. So kollidieren Sicherung/Import zwischen zwei Instanzen
+# praktisch nie, und der Code IST zugleich der Inhalt des QR /l/<code>.
+# Alphabet ohne 0/O/1/I/L – wie bei den Einzelstück-UIDs gut ablesbar.
+_LOCATION_CODE_ALPHABET = "ABCDEFGHJKMNPQRSTUVWXYZ23456789"
+
+
+def generate_location_code() -> str:
+    """Zufälliger 10-Zeichen-Code für einen Lagerort (Kollision vernachlässigbar)."""
+    return "".join(secrets.choice(_LOCATION_CODE_ALPHABET) for _ in range(10))
+
+
 class Location(Base):
    __tablename__ = "locations"

-    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    id: Mapped[str] = mapped_column(
+        String(10), primary_key=True, default=generate_location_code
+    )
    name: Mapped[str] = mapped_column(String(120), nullable=False)
    # Sub-locations (Regal/Fach) are a Schritt-3 feature; parent_id kept for forward-compat.
-    parent_id: Mapped[int | None] = mapped_column(
-        ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
+    parent_id: Mapped[str | None] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
    )


@@ -312,8 +327,8 @@ class Lot(Base):
        String(8), nullable=False, default=DatePrecision.day.value,
        server_default=DatePrecision.day.value,
    )
-    location_id: Mapped[int | None] = mapped_column(
-        ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
+    location_id: Mapped[str | None] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
    )
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)

@@ -339,8 +354,8 @@ class Movement(Base):
    note: Mapped[str | None] = mapped_column(String(255), nullable=True)
    # Bei Gegenstands-Buchungen der betroffene Lagerort (Lebensmittel führen den
    # Ort an der Charge/Lot). Nullable, damit bestehende Bewegungen gültig bleiben.
-    location_id: Mapped[int | None] = mapped_column(
-        ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
+    location_id: Mapped[str | None] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
    )
    # Grund einer Entnahme (lost/broken/…), nur bei type=out aus dem Entfernen-Dialog.
    # Als kurzer String, damit per ADD COLUMN nachziehbar (kein Postgres-Enumtyp).
@@ -527,8 +542,8 @@ class Item(Base):
    product_id: Mapped[int] = mapped_column(
        ForeignKey("products.id", ondelete="CASCADE"), nullable=False
    )
-    location_id: Mapped[int | None] = mapped_column(
-        ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
+    location_id: Mapped[str | None] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="SET NULL"), nullable=True
    )
    shop_id: Mapped[int | None] = mapped_column(
        ForeignKey("shops.id", ondelete="SET NULL"), nullable=True
@@ -583,8 +598,8 @@ class ProductLocationMinStock(Base):
    product_id: Mapped[int] = mapped_column(
        ForeignKey("products.id", ondelete="CASCADE"), nullable=False, index=True
    )
-    location_id: Mapped[int] = mapped_column(
-        ForeignKey("locations.id", ondelete="CASCADE"), nullable=False
+    location_id: Mapped[str] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="CASCADE"), nullable=False
    )
    # In Artikeleinheiten (Packungen/Stueck), wie in der Produktliste gezaehlt.
    min_stock: Mapped[float] = mapped_column(Float, nullable=False)
@@ -603,8 +618,8 @@ class GroupLocationMinStock(Base):
    group_id: Mapped[int] = mapped_column(
        ForeignKey("groups.id", ondelete="CASCADE"), nullable=False, index=True
    )
-    location_id: Mapped[int] = mapped_column(
-        ForeignKey("locations.id", ondelete="CASCADE"), nullable=False
+    location_id: Mapped[str] = mapped_column(
+        String(10), ForeignKey("locations.id", ondelete="CASCADE"), nullable=False
    )
    min_stock: Mapped[float] = mapped_column(Float, nullable=False)

--- a/backend/app/routers/items.py
+++ b/backend/app/routers/items.py
@@ -62,7 +62,7 @@ def _item_or_404(db: Session, item_id: int) -> Item:
    return item


-def _check_refs(db: Session, shop_id: int | None, location_id: int | None) -> None:
+def _check_refs(db: Session, shop_id: int | None, location_id: str | None) -> None:
    if shop_id is not None and db.get(Shop, shop_id) is None:
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Shop nicht gefunden")
    if location_id is not None and db.get(Location, location_id) is None:
--- a/backend/app/routers/locations.py
+++ b/backend/app/routers/locations.py
@@ -10,10 +10,10 @@ from ..schemas import LocationCreate, LocationOut, LocationUpdate
 router = APIRouter(prefix="/locations", tags=["locations"])


-def _descendant_ids(db: Session, location_id: int) -> set[int]:
+def _descendant_ids(db: Session, location_id: str) -> set[str]:
    """Alle Unterorte (rekursiv) – als Ziel beim Umhängen ausgeschlossen, sonst
    entstünde ein Ring."""
-    result: set[int] = set()
+    result: set[str] = set()
    stack = [location_id]
    while stack:
        cur = stack.pop()
@@ -46,7 +46,7 @@ def create_location(

@router.patch("/{location_id}", response_model=LocationOut)
 def update_location(
-    location_id: int,
+    location_id: str,
    payload: LocationUpdate,
    db: Session = Depends(get_db),
    _: User = Depends(require_admin),
@@ -93,7 +93,7 @@ def update_location(

@router.delete("/{location_id}", status_code=status.HTTP_204_NO_CONTENT)
 def delete_location(
-    location_id: int,
+    location_id: str,
    db: Session = Depends(get_db),
    _: User = Depends(require_admin),
 ) -> None:
--- a/backend/app/schemas.py
+++ b/backend/app/schemas.py
@@ -111,13 +111,13 @@ class UserUpdate(BaseModel):
 # ---- Groups ----
 class LocationMinStockIn(BaseModel):
    """Ein Mindestbestand-Eintrag je Lagerort (Menge in Artikeleinheiten)."""
-    location_id: int
+    location_id: str
    min_stock: float = Field(ge=0)


 class LocationMinStockOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
-    location_id: int
+    location_id: str
    location_name: str | None = None
    min_stock: float

@@ -239,19 +239,19 @@ class FieldDefinitionOut(BaseModel):
 # ---- Locations ----
 class LocationOut(BaseModel):
    model_config = ConfigDict(from_attributes=True)
-    id: int
+    id: str
    name: str
-    parent_id: int | None = None
+    parent_id: str | None = None


 class LocationCreate(BaseModel):
    name: str = Field(min_length=1, max_length=120)
-    parent_id: int | None = None
+    parent_id: str | None = None


 class LocationUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=120)
-    parent_id: int | None = None
+    parent_id: str | None = None


 # ---- Gebinde (Packung, Glas, …) ----
@@ -409,7 +409,7 @@ class CheckInRequest(BaseModel):
    best_before: date | None = None
    # "month" legt das MHD auf den Monatsletzten (siehe services/dates.py).
    best_before_precision: DatePrecision = DatePrecision.day
-    location_id: int | None = None
+    location_id: str | None = None
    note: str | None = None


@@ -430,7 +430,7 @@ class LotOut(BaseModel):
    quantity: float
    best_before: date | None
    best_before_precision: DatePrecision = DatePrecision.day
-    location_id: int | None
+    location_id: str | None
    created_at: datetime


@@ -439,7 +439,7 @@ class LotUpdate(BaseModel):
    quantity: float | None = Field(default=None, gt=0)
    best_before: date | None = None
    best_before_precision: DatePrecision | None = None
-    location_id: int | None = None
+    location_id: str | None = None


 class CheckInResponse(BaseModel):
@@ -452,7 +452,7 @@ class CheckInLine(BaseModel):
    quantity: float = Field(gt=0)
    best_before: date | None = None
    best_before_precision: DatePrecision = DatePrecision.day
-    location_id: int | None = None
+    location_id: str | None = None


 class BatchCheckInRequest(BaseModel):
@@ -479,8 +479,8 @@ class RelocateRequest(BaseModel):
    product_id: int | None = None
    barcode: str | None = None
    quantity: float = Field(gt=0)
-    from_location_id: int | None = None
-    to_location_id: int | None = None
+    from_location_id: str | None = None
+    to_location_id: str | None = None
    note: str | None = None


@@ -489,7 +489,7 @@ class RemoveRequest(BaseModel):
    product_id: int | None = None
    barcode: str | None = None
    quantity: float = Field(gt=0)
-    location_id: int | None = None
+    location_id: str | None = None
    reason: RemovalReason
    note: str | None = None

@@ -508,7 +508,7 @@ class RemovalStat(BaseModel):
 class RemovalHistoryItem(BaseModel):
    reason: RemovalReason
    quantity: float
-    location_id: int | None = None
+    location_id: str | None = None
    location_name: str | None = None
    note: str | None = None
    username: str | None = None
@@ -524,7 +524,7 @@ class RemovalSummary(BaseModel):
 class ItemCreate(BaseModel):
    """Ein oder mehrere Einzelstücke mit gemeinsamen Startwerten anlegen."""
    count: int = Field(default=1, ge=1, le=200)
-    location_id: int | None = None
+    location_id: str | None = None
    shop_id: int | None = None
    acquired_on: date | None = None
    warranty_until: date | None = None
@@ -534,7 +534,7 @@ class ItemCreate(BaseModel):


 class ItemUpdate(BaseModel):
-    location_id: int | None = None
+    location_id: str | None = None
    shop_id: int | None = None
    acquired_on: date | None = None
    warranty_until: date | None = None
@@ -578,7 +578,7 @@ class ItemOut(BaseModel):
    id: int
    uid: str
    product_id: int
-    location_id: int | None = None
+    location_id: str | None = None
    location_name: str | None = None
    shop_id: int | None = None
    shop_name: str | None = None
@@ -652,7 +652,7 @@ class LocationNeedGroup(BaseModel):

 class LocationNeeds(BaseModel):
    """Alle Bedarfe (Produkte + Gruppen) eines Lagerorts."""
-    location_id: int
+    location_id: str
    location_name: str
    products: list[LocationNeedProduct] = []
    groups: list[LocationNeedGroup] = []
--- a/backend/app/services/master_data.py
+++ b/backend/app/services/master_data.py
@@ -26,7 +26,9 @@ from .fields import options_list

 FORMAT_KEY = "vorrania_master_data"
 FORMAT_VERSION = 1
-_TABLES = ("units", "package_types", "categories", "field_definitions", "locations")
+# Nur Tabellen mit fortlaufender Integer-id brauchen die Sequenz-Korrektur.
+# Lagerorte tragen einen zufälligen Code als id – dort gibt es keine Sequenz.
+_TABLES = ("units", "package_types", "categories", "field_definitions")


 def export_master_data(db: Session) -> dict:
@@ -46,7 +48,7 @@ def export_master_data(db: Session) -> dict:
        ],
        "locations": [
            {"id": l.id, "name": l.name, "parent_id": l.parent_id}
-            for l in db.query(Location).order_by(Location.id).all()
+            for l in db.query(Location).order_by(Location.name).all()
        ],
        "units": [
            {"id": u.id, "name": u.name, "kind": u.kind.value, "factor": u.factor,
--- a/backend/app/services/stock.py
+++ b/backend/app/services/stock.py
@@ -34,7 +34,7 @@ class StockError(ValueError):
 # oben (check_in/check_out) bleibt davon unberührt.
 # ---------------------------------------------------------------------------

-def _object_lot(db: Session, product_id: int, location_id: int | None) -> Lot | None:
+def _object_lot(db: Session, product_id: int, location_id: str | None) -> Lot | None:
    """Die (einzige) Bestandszeile eines Gegenstands an einem Lagerort."""
    query = db.query(Lot).filter(
        Lot.product_id == product_id, Lot.best_before.is_(None)
@@ -50,7 +50,7 @@ def object_add(
    db: Session,
    product: Product,
    quantity: float,
-    location_id: int | None,
+    location_id: str | None,
    user: User | None,
    note: str | None = None,
 ) -> Lot:
@@ -86,7 +86,7 @@ def object_remove(
    db: Session,
    product: Product,
    quantity: float,
-    location_id: int | None,
+    location_id: str | None,
    reason: str,
    user: User | None,
    note: str | None = None,
@@ -121,8 +121,8 @@ def object_relocate(
    db: Session,
    product: Product,
    quantity: float,
-    from_location_id: int | None,
-    to_location_id: int | None,
+    from_location_id: str | None,
+    to_location_id: str | None,
    user: User | None,
    note: str | None = None,
 ) -> None:
@@ -215,7 +215,7 @@ def current_stock(db: Session, product_id: int) -> float:
    return float(sum(q for (q,) in total))


-def location_stock_base(db: Session, product: Product, location_id: int) -> float:
+def location_stock_base(db: Session, product: Product, location_id: str) -> float:
    """Bestand eines Produkts an EINEM Lagerort (in Basiseinheiten).

    Einzelstücke zählen die Items an diesem Ort, sonst werden die Lot-Mengen des
@@ -235,9 +235,9 @@ def location_stock_base(db: Session, product: Product, location_id: int) -> floa
    return float(sum(q for (q,) in total))


-def descendant_location_ids(db: Session, location_id: int) -> set[int]:
+def descendant_location_ids(db: Session, location_id: str) -> set[str]:
    """Alle Unter-Lagerorte (rekursiv) eines Lagerorts."""
-    result: set[int] = set()
+    result: set[str] = set()
    stack = [location_id]
    while stack:
        cur = stack.pop()
@@ -248,7 +248,7 @@ def descendant_location_ids(db: Session, location_id: int) -> set[int]:
    return result


-def location_subtree_stock_base(db: Session, product: Product, location_id: int) -> float:
+def location_subtree_stock_base(db: Session, product: Product, location_id: str) -> float:
    """Bestand an einem Lagerort INKL. aller Unter-Lagerorte (Basiseinheiten).

    So gilt ein Mindestbestand auf „Hedingen" als gedeckt, wenn der Vorrat
@@ -264,7 +264,7 @@ def check_in(
    quantity: float,
    unit: str,
    best_before: date | None,
-    location_id: int | None,
+    location_id: str | None,
    user: User | None,
    note: str | None = None,
    best_before_precision: str | None = DatePrecision.day.value,
--- a/backend/tests/test_locations.py
+++ b/backend/tests/test_locations.py
@@ -31,6 +31,17 @@ def _orte(db):
    return keller, regal, fach


+def test_neuer_ort_bekommt_10_zeichen_code_als_id(db):
+    ort = Location(name="Speisekammer")
+    db.add(ort)
+    db.commit()
+    # Statt fortlaufender Zahl trägt der Lagerort einen zufälligen Code – das
+    # macht Sicherung/Import zwischen zwei Instanzen konfliktfrei.
+    assert isinstance(ort.id, str)
+    assert len(ort.id) == 10
+    assert set(ort.id) <= set("ABCDEFGHJKMNPQRSTUVWXYZ23456789")
+
+
 def test_umbenennen_ohne_parent_bleibt_hierarchie(db, admin):
    keller, regal, _ = _orte(db)
    out = update_location(regal.id, LocationUpdate(name="Regal links"), db=db, _=admin)
@@ -67,5 +78,5 @@ def test_umhaengen_in_eigenen_unterort_wird_abgelehnt(db, admin):
 def test_umhaengen_auf_unbekannten_ort_ist_404(db, admin):
    _, _, fach = _orte(db)
    with pytest.raises(HTTPException) as ex:
-        update_location(fach.id, LocationUpdate(parent_id=99999), db=db, _=admin)
+        update_location(fach.id, LocationUpdate(parent_id="ZZZZZZZZZZ"), db=db, _=admin)
    assert ex.value.status_code == 404
--- a/ios/Sources/APIClient.swift
+++ b/ios/Sources/APIClient.swift
@@ -435,19 +435,19 @@ actor APIClient {
        return try await send(request, as: StorageLocation.self)
    }

-    func renameLocation(id: Int, name: String) async throws -> StorageLocation {
+    func renameLocation(id: String, name: String) async throws -> StorageLocation {
        var request = try makeRequest("/locations/\(id)", method: "PATCH")
        try jsonBody(&request, RenameRequest(name: name))
        return try await send(request, as: StorageLocation.self)
    }

-    func updateLocation(id: Int, _ payload: LocationUpdateRequest) async throws -> StorageLocation {
+    func updateLocation(id: String, _ payload: LocationUpdateRequest) async throws -> StorageLocation {
        var request = try makeRequest("/locations/\(id)", method: "PATCH")
        try jsonBody(&request, payload)
        return try await send(request, as: StorageLocation.self)
    }

-    func deleteLocation(id: Int) async throws {
+    func deleteLocation(id: String) async throws {
        try await sendNoContent(try makeRequest("/locations/\(id)", method: "DELETE"))
    }

--- a/ios/Sources/AssignScanView.swift
+++ b/ios/Sources/AssignScanView.swift
@@ -58,17 +58,18 @@ struct AssignScanView: View {
    }

    private func handle(_ code: String) async {
-        // Lagerort-QR (…/l/<ID>)?
+        // Lagerort-QR (…/l/<Code>)? Der Code ist eine 10-stellige Zeichenkette.
        if let r = code.range(of: "/l/") {
-            let idStr = String(code[r.upperBound...])
+            let locCode = String(code[r.upperBound...])
                .trimmingCharacters(in: CharacterSet(charactersIn: "/ "))
-            if let locId = Int(idStr) {
+                .uppercased()
+            if !locCode.isEmpty {
                guard let it = pending else {
                    error = "Erst ein Einzelstück scannen."; status = nil; return
                }
                do {
                    _ = try await APIClient.shared.updateItem(id: it.id, ItemUpdateRequest(
-                        locationId: locId, shopId: it.shopId,
+                        locationId: locCode, shopId: it.shopId,
                        acquiredOn: it.acquiredOn, warrantyUntil: it.warrantyUntil, note: it.note))
                    status = "\(it.uid) zugeordnet. Nächstes Stück scannen."
                    error = nil
--- a/ios/Sources/CheckInFormView.swift
+++ b/ios/Sources/CheckInFormView.swift
@@ -153,10 +153,18 @@ struct CheckInFormView: View {
    /// Charge, fuer die gerade das MHD abgescannt wird.
    @State private var scanLineId: LineRef?
    @State private var unit: String = ""
-    @State private var locationId: Int?
+    @State private var locationId: String?
    @State private var busy = false
    @State private var error: String?

+    // Lagerort per QR (…/l/<Code>) setzen, statt in der Liste zu suchen.
+    @State private var locScanShown = false
+    @State private var locScanPaused = false
+    @State private var locTorchOn = false
+    @State private var locTorchLocked = false
+    @State private var locScanError: String?
+    @State private var locScanHinweis: String?
+
    /// Einheiten der passenden Art plus das Gebinde des Artikels.
    private var unitOptions: [UnitOption] {
        var options = units
@@ -189,13 +197,31 @@ struct CheckInFormView: View {
                Picker("Einheit", selection: $unit) {
                    ForEach(unitOptions) { Text($0.label).tag($0.value) }
                }
-                if !locations.isEmpty {
+            }
+
+            if !locations.isEmpty {
+                Section {
                    Picker("Lagerort", selection: $locationId) {
-                        Text("– keiner –").tag(Int?.none)
+                        Text("– keiner –").tag(String?.none)
                        ForEach(locations) { location in
-                            Text(location.name).tag(Int?.some(location.id))
+                            Text(location.name).tag(String?.some(location.id))
                        }
                    }
+                    Button {
+                        locScanError = nil
+                        locScanPaused = false
+                        locScanShown = true
+                    } label: {
+                        Label("Lagerort-QR scannen", systemImage: "qrcode.viewfinder")
+                    }
+                    if let locScanHinweis {
+                        Label(locScanHinweis, systemImage: "checkmark.circle.fill")
+                            .font(.caption).foregroundStyle(.green)
+                    }
+                } header: {
+                    Text("Lagerort")
+                } footer: {
+                    Text("Den QR am Regal/Fach scannen, statt den Ort in der Liste zu suchen.")
                }
            }

@@ -281,6 +307,7 @@ struct CheckInFormView: View {
                }
            }
        }
+        .fullScreenCover(isPresented: $locScanShown) { locationScannerCover }
        .onAppear {
            // Gibt es ein Gebinde, ist das die naheliegende Eingabe.
            unit = hasPackage ? UnitOption.packageValue : product.unitName
@@ -289,6 +316,60 @@ struct CheckInFormView: View {
        }
    }

+    // MARK: - Lagerort scannen
+
+    private var locationScannerCover: some View {
+        NavigationStack {
+            ScannerView(onCode: { code in Task { await handleLocationScan(code) } },
+                        isPaused: $locScanPaused, torchOn: $locTorchOn, torchLocked: $locTorchLocked)
+                .ignoresSafeArea(edges: .bottom)
+                .overlay(alignment: .bottom) {
+                    VStack(spacing: 6) {
+                        if let locScanError {
+                            Text(locScanError)
+                                .font(.callout).foregroundStyle(.white)
+                                .padding(.horizontal, 12).padding(.vertical, 8)
+                                .background(.red, in: Capsule())
+                        }
+                        Text("QR am Regal/Fach vor die Kamera halten")
+                            .font(.callout)
+                            .padding(10)
+                            .background(.ultraThinMaterial, in: Capsule())
+                    }
+                    .padding(.bottom, 24)
+                }
+                .navigationTitle("Lagerort scannen")
+                .navigationBarTitleDisplayMode(.inline)
+                .toolbar {
+                    ToolbarItem(placement: .topBarLeading) {
+                        Button("Abbrechen") { locScanShown = false }
+                    }
+                    ToolbarItem(placement: .topBarTrailing) {
+                        TorchButton(isOn: $locTorchOn, locked: $locTorchLocked)
+                    }
+                }
+        }
+        .onAppear { locScanPaused = false; locScanError = nil }
+    }
+
+    /// Aus einem gescannten Lagerort-QR (…/l/<Code>) den Zielort setzen.
+    private func handleLocationScan(_ code: String) async {
+        guard let r = code.range(of: "/l/") else {
+            locScanError = "Das ist kein Lagerort-QR."
+            return
+        }
+        let ziel = String(code[r.upperBound...])
+            .trimmingCharacters(in: CharacterSet(charactersIn: "/ "))
+            .uppercased()
+        if let treffer = locations.first(where: { $0.id == ziel }) {
+            locationId = treffer.id
+            locScanHinweis = treffer.name
+            locScanShown = false
+        } else {
+            locScanError = "Dieser Lagerort ist hier nicht bekannt."
+        }
+    }
+
    private func format(_ value: Double) -> String {
        value == value.rounded() ? String(Int(value)) : String(format: "%.2f", value)
    }
--- a/ios/Sources/CheckInView.swift
+++ b/ios/Sources/CheckInView.swift
@@ -3,9 +3,12 @@ import SwiftUI
 struct CheckInView: View {
    @Environment(\.dismiss) private var dismiss

+    // Kamera bewusst nur auf Wunsch: „Einlagern“ öffnet ein Formular, kein Sucher.
+    @State private var scanShown = false
    @State private var paused = false
    @State private var torchOn = false
    @State private var torchLocked = false
+
    @State private var status: String?
    @State private var error: String?

@@ -19,68 +22,103 @@ struct CheckInView: View {
    @State private var unknownCode: String?
    @State private var manualCodeShown = false
    @State private var manualCode = ""
+
+    // Manuelle Artikelsuche (statt Scanzwang).
+    @State private var query = ""
+    @State private var results: [Product] = []
+    @State private var searching = false
+
    @State private var units: [Unit] = []
    @State private var locations: [StorageLocation] = []

    var body: some View {
-        // Kamera bewusst nur als Feld oben statt bildschirmfuellend - der
-        // Sucher ueber die ganze Flaeche wirkte erschlagend.
-        ScrollView {
-            VStack(spacing: 14) {
-                ScannerView(onCode: { code in Task { await resolve(code) } },
-                            isPaused: $paused, torchOn: $torchOn, torchLocked: $torchLocked)
-                    .aspectRatio(4.0 / 3.0, contentMode: .fit)
-                    .clipShape(RoundedRectangle(cornerRadius: 16))
-                    .padding(.horizontal)
+        Form {
+            if let status { Section { banner(status, color: .green) } }
+            if let error { Section { banner(error, color: .red) } }

-                Text("Barcode vor die Kamera halten")
-                    .font(.caption).foregroundStyle(.secondary)
+            Section {
+                Button {
+                    error = nil; status = nil
+                    scanShown = true
+                } label: {
+                    Label("EAN scannen", systemImage: "barcode.viewfinder")
+                        .frame(maxWidth: .infinity)
+                }
+                .buttonStyle(.borderedProminent)

-                if let status { banner(status, color: .green) }
-                if let error { banner(error, color: .red) }
-
-                if let suggestion {
-                    suggestionCard(suggestion)
-                } else if let unknownCode {
-                    unknownCard(unknownCode)
+                Button {
+                    manualCode = ""
+                    manualCodeShown = true
+                } label: {
+                    Label("EAN von Hand eingeben", systemImage: "keyboard")
                }

-                VStack(spacing: 10) {
-                    Button {
-                        paused = true
-                        manualCodeShown = true
-                    } label: {
-                        Label("EAN manuell", systemImage: "keyboard")
-                            .frame(maxWidth: .infinity)
+                NavigationLink {
+                    ProductFormView(prefillBarcode: nil, groupId: nil) { created in
+                        product = created
                    }
-                    .buttonStyle(.borderedProminent)
-
-                    NavigationLink {
-                        ProductFormView(prefillBarcode: nil, groupId: nil) { created in
-                            product = created
-                        }
-                    } label: {
-                        Label("Artikel anlegen", systemImage: "plus")
-                            .frame(maxWidth: .infinity)
-                    }
-                    .buttonStyle(.bordered)
+                } label: {
+                    Label("Neuen Artikel anlegen", systemImage: "plus")
                }
-                .padding(.horizontal)
+            } header: {
+                Text("Neu erfassen")
+            } footer: {
+                Text("Die Kamera öffnet sich erst beim Tippen auf „EAN scannen“ – kein Zwang.")
+            }
+
+            if let suggestion {
+                suggestionSection(suggestion)
+            } else if let unknownCode {
+                unknownSection(unknownCode)
+            }
+
+            Section {
+                HStack {
+                    Image(systemName: "magnifyingglass").foregroundStyle(.secondary)
+                    TextField("Name oder Marke …", text: $query)
+                        .autocorrectionDisabled()
+                    if !query.isEmpty {
+                        Button { query = "" } label: {
+                            Image(systemName: "xmark.circle.fill").foregroundStyle(.secondary)
+                        }
+                        .buttonStyle(.plain)
+                    }
+                }
+                if searching {
+                    HStack { ProgressView(); Text("Suche …").foregroundStyle(.secondary) }
+                }
+                ForEach(results) { p in
+                    Button {
+                        error = nil; status = nil
+                        product = p
+                    } label: {
+                        VStack(alignment: .leading, spacing: 2) {
+                            Text(p.name).foregroundStyle(.primary)
+                            let unter = [p.brand, "Bestand: \(bestandText(p))"]
+                                .compactMap { $0 }.joined(separator: " · ")
+                            Text(unter).font(.caption).foregroundStyle(.secondary)
+                        }
+                    }
+                }
+                if !query.trimmingCharacters(in: .whitespaces).isEmpty && results.isEmpty && !searching {
+                    Text("Kein Artikel gefunden – oben neu anlegen.")
+                        .foregroundStyle(.secondary).font(.callout)
+                }
+            } header: {
+                Text("Vorhandenen Artikel wählen")
            }
-            .padding(.vertical)
        }
        .navigationTitle("Einlagern")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
-            ToolbarItem(placement: .topBarLeading) {
-                Button("Fertig") { dismiss() }
-            }
-            ToolbarItem(placement: .topBarTrailing) { TorchButton(isOn: $torchOn, locked: $torchLocked) }
+            ToolbarItem(placement: .topBarLeading) { Button("Fertig") { dismiss() } }
        }
        .task {
            units = (try? await APIClient.shared.units()) ?? []
            locations = (try? await APIClient.shared.locations()) ?? []
        }
+        .task(id: query) { await search() }
+        .fullScreenCover(isPresented: $scanShown) { scannerCover }
        .alert("EAN eingeben", isPresented: $manualCodeShown) {
            TextField("z.B. 8076809572569", text: $manualCode)
                .keyboardType(.numberPad)
@@ -89,22 +127,49 @@ struct CheckInView: View {
                manualCode = ""
                Task { await resolve(code) }
            }
-            Button("Abbrechen", role: .cancel) { paused = false }
+            Button("Abbrechen", role: .cancel) { }
        }
        .sheet(item: $product) { item in
            NavigationStack {
                CheckInFormView(product: item, units: units, locations: locations) { message in
                    status = message
                    product = nil
-                    paused = false
                }
            }
        }
-        .sheet(item: $scannedItem, onDismiss: { paused = false }) { it in
+        .sheet(item: $scannedItem) { it in
            NavigationStack { ItemEditView(item: it) }
        }
    }

+    // MARK: - Scanner (nur auf Wunsch)
+
+    private var scannerCover: some View {
+        NavigationStack {
+            ScannerView(onCode: { code in Task { await resolve(code) } },
+                        isPaused: $paused, torchOn: $torchOn, torchLocked: $torchLocked)
+                .ignoresSafeArea(edges: .bottom)
+                .overlay(alignment: .bottom) {
+                    Text("Barcode vor die Kamera halten")
+                        .font(.callout)
+                        .padding(10)
+                        .background(.ultraThinMaterial, in: Capsule())
+                        .padding(.bottom, 24)
+                }
+                .navigationTitle("EAN scannen")
+                .navigationBarTitleDisplayMode(.inline)
+                .toolbar {
+                    ToolbarItem(placement: .topBarLeading) {
+                        Button("Abbrechen") { scanShown = false }
+                    }
+                    ToolbarItem(placement: .topBarTrailing) {
+                        TorchButton(isOn: $torchOn, locked: $torchLocked)
+                    }
+                }
+        }
+        .onAppear { paused = false }
+    }
+
    // MARK: - Bausteine

    private func banner(_ text: String, color: Color) -> some View {
@@ -115,7 +180,14 @@ struct CheckInView: View {
            .background(color.opacity(0.9))
            .foregroundStyle(.white)
            .clipShape(RoundedRectangle(cornerRadius: 10))
-            .padding(.horizontal)
+            .listRowInsets(EdgeInsets())
+            .listRowBackground(Color.clear)
+    }
+
+    private func bestandText(_ p: Product) -> String {
+        let wert = p.stockInArticleUnits
+        let zahl = wert == wert.rounded() ? String(Int(wert)) : String(format: "%.2f", wert)
+        return "\(zahl) \(p.articleUnitLabel)"
    }

    /// Sagt vor dem Anlegen, welche Gruppe der Artikel bekommt und warum.
@@ -141,64 +213,73 @@ struct CheckInView: View {
                Text(detail).font(.caption2).foregroundStyle(.secondary)
            }
        }
-        .padding(8)
-        .frame(maxWidth: .infinity, alignment: .leading)
-        .background(Color.accentColor.opacity(0.15))
-        .clipShape(RoundedRectangle(cornerRadius: 8))
    }

-    private func suggestionCard(_ item: LookupResult.Suggestion) -> some View {
-        VStack(alignment: .leading, spacing: 8) {
-            Text(item.name).font(.headline)
-            Text([item.brand, item.quantityText].compactMap { $0 }.joined(separator: " · "))
-                .font(.caption).foregroundStyle(.secondary)
-            Text("In einer Produkt-Datenbank gefunden, noch nicht im Katalog.")
-                .font(.caption2).foregroundStyle(.secondary)
-            groupNote()
-            NavigationLink {
-                ProductFormView(prefillBarcode: item.barcode, groupId: suggestedGroupId,
-                                categoryId: suggestedCategoryId, suggestion: item) { created in
-                    suggestion = nil
-                    product = created
+    @ViewBuilder
+    private func suggestionSection(_ item: LookupResult.Suggestion) -> some View {
+        Section {
+            VStack(alignment: .leading, spacing: 8) {
+                Text(item.name).font(.headline)
+                Text([item.brand, item.quantityText].compactMap { $0 }.joined(separator: " · "))
+                    .font(.caption).foregroundStyle(.secondary)
+                Text("In einer Produkt-Datenbank gefunden, noch nicht im Katalog.")
+                    .font(.caption2).foregroundStyle(.secondary)
+                groupNote()
+                NavigationLink {
+                    ProductFormView(prefillBarcode: item.barcode, groupId: suggestedGroupId,
+                                    categoryId: suggestedCategoryId, suggestion: item) { created in
+                        suggestion = nil
+                        product = created
+                    }
+                } label: {
+                    Label("Anlegen & einlagern", systemImage: "plus.circle.fill")
+                        .frame(maxWidth: .infinity)
                }
-            } label: {
-                Label("Anlegen & einlagern", systemImage: "plus.circle.fill")
-                    .frame(maxWidth: .infinity)
+                .buttonStyle(.borderedProminent)
            }
-            .buttonStyle(.borderedProminent)
+        } header: {
+            Text("Vorschlag zum Scan")
        }
-        .padding()
-        .background(.thinMaterial)
-        .clipShape(RoundedRectangle(cornerRadius: 12))
-        .padding(.horizontal)
    }

-    private func unknownCard(_ code: String) -> some View {
-        VStack(alignment: .leading, spacing: 8) {
-            Text("Unbekannter Code \(code)").font(.headline)
-            Text("Weder im Katalog noch in Open Food / Products Facts.")
-                .font(.caption).foregroundStyle(.secondary)
-            groupNote()
-            NavigationLink {
-                ProductFormView(prefillBarcode: code, groupId: suggestedGroupId,
-                                categoryId: suggestedCategoryId) { created in
-                    unknownCode = nil
-                    product = created
+    @ViewBuilder
+    private func unknownSection(_ code: String) -> some View {
+        Section {
+            VStack(alignment: .leading, spacing: 8) {
+                Text("Unbekannter Code \(code)").font(.headline)
+                Text("Weder im Katalog noch in Open Food / Products Facts.")
+                    .font(.caption).foregroundStyle(.secondary)
+                groupNote()
+                NavigationLink {
+                    ProductFormView(prefillBarcode: code, groupId: suggestedGroupId,
+                                    categoryId: suggestedCategoryId) { created in
+                        unknownCode = nil
+                        product = created
+                    }
+                } label: {
+                    Label("Artikel anlegen", systemImage: "plus")
+                        .frame(maxWidth: .infinity)
                }
-            } label: {
-                Label("Artikel anlegen", systemImage: "plus")
-                    .frame(maxWidth: .infinity)
+                .buttonStyle(.borderedProminent)
            }
-            .buttonStyle(.borderedProminent)
+        } header: {
+            Text("Zum Scan")
        }
-        .padding()
-        .background(.thinMaterial)
-        .clipShape(RoundedRectangle(cornerRadius: 12))
-        .padding(.horizontal)
    }

    // MARK: - Logik

+    private func search() async {
+        let q = query.trimmingCharacters(in: .whitespaces)
+        guard q.count >= 2 else { results = []; searching = false; return }
+        // Kurze Verzögerung, damit nicht bei jedem Tastendruck abgefragt wird.
+        try? await Task.sleep(nanoseconds: 250_000_000)
+        if Task.isCancelled { return }
+        searching = true
+        defer { searching = false }
+        results = (try? await APIClient.shared.searchProducts(q)) ?? []
+    }
+
    private func resolve(_ code: String) async {
        paused = true
        error = nil
@@ -213,6 +294,7 @@ struct CheckInView: View {
                    .uppercased()
                if !uid.isEmpty, let item = try? await APIClient.shared.itemByUid(uid: uid) {
                    scannedItem = item
+                    scanShown = false
                    return
                }
            }
@@ -228,9 +310,10 @@ struct CheckInView: View {
            } else {
                unknownCode = code
            }
+            scanShown = false
        } catch {
            self.error = error.localizedDescription
-            paused = false
+            scanShown = false
        }
    }
 }
--- a/ios/Sources/ItemViews.swift
+++ b/ios/Sources/ItemViews.swift
@@ -92,7 +92,7 @@ struct ItemEditView: View {
    @State private var locations: [StorageLocation] = []
    @State private var shops: [ShopItem] = []
    @State private var photo: Data?
-    @State private var locationId: Int?
+    @State private var locationId: String?
    @State private var shopId: Int?
    @State private var hasAcquired = false
    @State private var acquired = Date()
@@ -138,8 +138,8 @@ struct ItemEditView: View {

            Section {
                Picker("Lagerort", selection: $locationId) {
-                    Text("– ohne –").tag(Int?.none)
-                    ForEach(locations) { l in Text(l.name).tag(Int?.some(l.id)) }
+                    Text("– ohne –").tag(String?.none)
+                    ForEach(locations) { l in Text(l.name).tag(String?.some(l.id)) }
                }
                Picker("Gekauft bei", selection: $shopId) {
                    Text("– unbekannt –").tag(Int?.none)
@@ -406,7 +406,7 @@ struct ItemAddSheet: View {
    @State private var count = 1
    @State private var locations: [StorageLocation] = []
    @State private var shops: [ShopItem] = []
-    @State private var locationId: Int?
+    @State private var locationId: String?
    @State private var shopId: Int?
    @State private var hasAcquired = false
    @State private var acquired = Date()
@@ -430,8 +430,8 @@ struct ItemAddSheet: View {
            Section {
                Stepper("Anzahl: \(count)", value: $count, in: 1...200)
                Picker("Lagerort", selection: $locationId) {
-                    Text("– ohne –").tag(Int?.none)
-                    ForEach(locations) { l in Text(l.name).tag(Int?.some(l.id)) }
+                    Text("– ohne –").tag(String?.none)
+                    ForEach(locations) { l in Text(l.name).tag(String?.some(l.id)) }
                }
                Picker("Gekauft bei", selection: $shopId) {
                    Text("– unbekannt –").tag(Int?.none)
--- a/ios/Sources/MasterDataViews.swift
+++ b/ios/Sources/MasterDataViews.swift
@@ -181,7 +181,7 @@ struct TreeMasterView<Item: TreeItem, Header: View, Editor: View>: View {
    let title: String
    let singular: String
    let load: () async throws -> [Item]
-    let delete: (Int) async throws -> Void
+    let delete: (Item.ID) async throws -> Void
    /// Optionaler kleiner Hinweis am Zeilenende (z. B. der Kategorie-Typ).
    let badge: (Item) -> String?
    /// Nur Einträge, die das erfüllen, werden gezeigt (z. B. der Typ-Filter).
@@ -190,7 +190,7 @@ struct TreeMasterView<Item: TreeItem, Header: View, Editor: View>: View {
    @ViewBuilder let editor: (_ editing: Item?, _ all: [Item], _ done: @escaping () -> Void) -> Editor

    @State private var items: [Item] = []
-    @State private var collapsed: Set<Int> = []
+    @State private var collapsed: Set<Item.ID> = []
    @State private var busy = true
    @State private var error: String?
    @State private var editing: Item?
@@ -200,7 +200,7 @@ struct TreeMasterView<Item: TreeItem, Header: View, Editor: View>: View {
    private struct Node: Identifiable {
        let item: Item
        let depth: Int
-        var id: Int { item.id }
+        var id: Item.ID { item.id }
    }

    private var shown: [Item] { items.filter(include) }
@@ -221,11 +221,11 @@ struct TreeMasterView<Item: TreeItem, Header: View, Editor: View>: View {
        return result
    }

-    private func childCount(_ id: Int) -> Int { shown.filter { $0.parentId == id }.count }
+    private func childCount(_ id: Item.ID) -> Int { shown.filter { $0.parentId == id }.count }

    private var visible: [Node] {
        let parent = Dictionary(uniqueKeysWithValues: shown.map { ($0.id, $0.parentId) })
-        func hidden(_ id: Int) -> Bool {
+        func hidden(_ id: Item.ID) -> Bool {
            var p = parent[id] ?? nil
            while let cur = p {
                if collapsed.contains(cur) { return true }
@@ -324,7 +324,7 @@ struct TreeMasterView<Item: TreeItem, Header: View, Editor: View>: View {
        .padding(.leading, CGFloat(node.depth) * 16)
    }

-    private func toggle(_ id: Int) {
+    private func toggle(_ id: Item.ID) {
        if collapsed.contains(id) { collapsed.remove(id) } else { collapsed.insert(id) }
    }

@@ -441,7 +441,7 @@ struct LocationEditor: View {
    let done: () -> Void

    @State private var name: String
-    @State private var parentId: Int?
+    @State private var parentId: String?
    @State private var error: String?
    @State private var busy = false

@@ -467,9 +467,9 @@ struct LocationEditor: View {
                }
                Section {
                    Picker("Übergeordnet", selection: $parentId) {
-                        Text("– oberste Ebene –").tag(Int?.none)
+                        Text("– oberste Ebene –").tag(String?.none)
                        ForEach(parentOptions) { loc in
-                            Text(LocationEditor.pfad(loc, in: all)).tag(Int?.some(loc.id))
+                            Text(LocationEditor.pfad(loc, in: all)).tag(String?.some(loc.id))
                        }
                    }
                } header: {
@@ -513,8 +513,8 @@ struct LocationEditor: View {
    }

    /// Alle Unterorte (rekursiv) – als Ziel beim Umhängen ausgeschlossen.
-    private static func descendants(of id: Int, in all: [StorageLocation]) -> Set<Int> {
-        var result: Set<Int> = []
+    private static func descendants(of id: String, in all: [StorageLocation]) -> Set<String> {
+        var result: Set<String> = []
        var stack = [id]
        while let cur = stack.popLast() {
            for kid in all where kid.parentId == cur {
--- a/ios/Sources/Models.swift
+++ b/ios/Sources/Models.swift
@@ -134,10 +134,10 @@ struct Product: Codable, Identifiable, Hashable {

 /// Mindestbestand eines Produkts/einer Gruppe an einem Lagerort (Anzeige).
 struct LocationMinStock: Codable, Hashable, Identifiable {
-    let locationId: Int
+    let locationId: String
    let locationName: String?
    let minStock: Double
-    var id: Int { locationId }
+    var id: String { locationId }

    enum CodingKeys: String, CodingKey {
        case minStock = "min_stock"
@@ -148,7 +148,7 @@ struct LocationMinStock: Codable, Hashable, Identifiable {

 /// Ein Mindestbestand-Eintrag zum Speichern (Menge in Artikeleinheiten).
 struct LocationMinStockIn: Codable {
-    let locationId: Int
+    let locationId: String
    let minStock: Double

    enum CodingKeys: String, CodingKey {
@@ -217,7 +217,7 @@ struct Lot: Codable, Identifiable, Hashable {
    let quantity: Double
    let bestBefore: String?
    let bestBeforePrecision: String?
-    let locationId: Int?
+    let locationId: String?

    enum CodingKeys: String, CodingKey {
        case id, quantity
@@ -229,9 +229,9 @@ struct Lot: Codable, Identifiable, Hashable {
 }

 struct StorageLocation: Codable, Identifiable, Hashable {
-    let id: Int
+    let id: String
    let name: String
-    let parentId: Int?
+    let parentId: String?

    enum CodingKeys: String, CodingKey {
        case id, name
@@ -243,7 +243,7 @@ struct CheckInLine: Codable {
    let quantity: Double
    let bestBefore: String?
    let bestBeforePrecision: String
-    let locationId: Int?
+    let locationId: String?

    enum CodingKeys: String, CodingKey {
        case quantity
@@ -391,12 +391,12 @@ struct LocationNeedGroup: Codable, Identifiable {
 }

 struct LocationNeeds: Codable, Identifiable {
-    let locationId: Int
+    let locationId: String
    let locationName: String
    let products: [LocationNeedProduct]
    let groups: [LocationNeedGroup]

-    var id: Int { locationId }
+    var id: String { locationId }

    enum CodingKeys: String, CodingKey {
        case products, groups
@@ -531,9 +531,9 @@ struct CategoryItem: Codable, Identifiable, Hashable {

 /// Gemeinsame Form baumartiger Stammdaten (Kategorien, Lagerorte): eine flache
 /// Liste mit Eltern-Verweis, aus der sich der Baum aufbauen lässt.
-protocol TreeItem: Identifiable where ID == Int {
+protocol TreeItem: Identifiable {
    var name: String { get }
-    var parentId: Int? { get }
+    var parentId: ID? { get }
 }

 extension CategoryItem: TreeItem {}
@@ -580,7 +580,7 @@ struct ObjectCheckInRequest: Codable {
    let productId: Int
    let quantity: Double
    let unit: String
-    let locationId: Int?
+    let locationId: String?

    enum CodingKeys: String, CodingKey {
        case quantity, unit
@@ -592,8 +592,8 @@ struct ObjectCheckInRequest: Codable {
 struct RelocateRequest: Codable {
    let productId: Int
    let quantity: Double
-    let fromLocationId: Int?
-    let toLocationId: Int?
+    let fromLocationId: String?
+    let toLocationId: String?

    enum CodingKeys: String, CodingKey {
        case quantity
@@ -606,7 +606,7 @@ struct RelocateRequest: Codable {
 struct RemoveRequest: Codable {
    let productId: Int
    let quantity: Double
-    let locationId: Int?
+    let locationId: String?
    let reason: String
    let note: String?

@@ -627,7 +627,7 @@ struct RemovalStat: Codable, Identifiable, Hashable {
 struct RemovalHistoryItem: Codable, Identifiable, Hashable {
    let reason: String
    let quantity: Double
-    let locationId: Int?
+    let locationId: String?
    let locationName: String?
    let note: String?
    let username: String?
@@ -681,7 +681,7 @@ struct Item: Codable, Identifiable, Hashable {
    let id: Int
    let uid: String
    let productId: Int
-    let locationId: Int?
+    let locationId: String?
    let locationName: String?
    let shopId: Int?
    let shopName: String?
@@ -757,7 +757,7 @@ struct ItemDocumentUpload: Codable {

 struct ItemCreateRequest: Codable {
    let count: Int
-    let locationId: Int?
+    let locationId: String?
    let shopId: Int?
    let acquiredOn: String?
    let warrantyUntil: String?
@@ -776,7 +776,7 @@ struct ItemCreateRequest: Codable {
 }

 struct ItemUpdateRequest: Encodable {
-    var locationId: Int?
+    var locationId: String?
    var shopId: Int?
    var acquiredOn: String?
    var warrantyUntil: String?
@@ -996,7 +996,7 @@ struct PackageType: Codable, Identifiable, Hashable {

 struct NewLocationRequest: Codable {
    let name: String
-    let parentId: Int?
+    let parentId: String?

    enum CodingKeys: String, CodingKey {
        case name
@@ -1008,7 +1008,7 @@ struct NewLocationRequest: Codable {
 /// (auch `null` = oberste Ebene), damit „auf oberste Ebene holen" ankommt.
 struct LocationUpdateRequest: Codable {
    let name: String
-    let parentId: Int?
+    let parentId: String?

    enum CodingKeys: String, CodingKey {
        case name
--- a/ios/Sources/ObjectStockView.swift
+++ b/ios/Sources/ObjectStockView.swift
@@ -15,19 +15,19 @@ struct ObjectStockSection: View {

    enum StockSheet: Identifiable {
        case add
-        case relocate(from: Int?)
-        case remove(loc: Int?)
+        case relocate(from: String?)
+        case remove(loc: String?)
        var id: String {
            switch self {
            case .add: return "add"
-            case .relocate(let f): return "relocate-\(f.map(String.init) ?? "none")"
-            case .remove(let l): return "remove-\(l.map(String.init) ?? "none")"
+            case .relocate(let f): return "relocate-\(f ?? "none")"
+            case .remove(let l): return "remove-\(l ?? "none")"
            }
        }
    }

    private var einheit: String { product.unitName.isEmpty ? "Stück" : product.unitName }
-    private func ortName(_ id: Int?) -> String {
+    private func ortName(_ id: String?) -> String {
        guard let id else { return "Ohne Lagerort" }
        return locations.first { $0.id == id }?.name ?? "Ort \(id)"
    }
@@ -170,12 +170,12 @@ struct ObjectFieldRow: View {
 private struct LocationPicker: View {
    let title: String
    let locations: [StorageLocation]
-    @Binding var selection: Int?
+    @Binding var selection: String?

    var body: some View {
        Picker(title, selection: $selection) {
-            Text("– ohne Lagerort –").tag(Int?.none)
-            ForEach(locations) { loc in Text(loc.name).tag(Int?.some(loc.id)) }
+            Text("– ohne Lagerort –").tag(String?.none)
+            ForEach(locations) { loc in Text(loc.name).tag(String?.some(loc.id)) }
        }
    }
 }
@@ -188,7 +188,7 @@ struct ObjectAddSheet: View {
    var perform: () async -> Void

    @Environment(\.dismiss) private var dismiss
-    @State private var locationId: Int?
+    @State private var locationId: String?
    @State private var quantity = ""
    @State private var busy = false
    @State private var error: String?
@@ -229,12 +229,12 @@ struct ObjectAddSheet: View {
 struct ObjectRelocateSheet: View {
    let product: Product
    let locations: [StorageLocation]
-    let initialFrom: Int?
+    let initialFrom: String?
    var perform: () async -> Void

    @Environment(\.dismiss) private var dismiss
-    @State private var fromId: Int?
-    @State private var toId: Int?
+    @State private var fromId: String?
+    @State private var toId: String?
    @State private var quantity = ""
    @State private var busy = false
    @State private var error: String?
@@ -277,11 +277,11 @@ struct ObjectRemoveSheet: View {
    let product: Product
    let locations: [StorageLocation]
    let einheit: String
-    let initialLoc: Int?
+    let initialLoc: String?
    var perform: () async -> Void

    @Environment(\.dismiss) private var dismiss
-    @State private var locationId: Int?
+    @State private var locationId: String?
    @State private var quantity = ""
    @State private var reason = "broken"
    @State private var note = ""
--- a/ios/Sources/ProductDetailView.swift
+++ b/ios/Sources/ProductDetailView.swift
@@ -424,7 +424,7 @@ struct ProductLocationMinView: View {

    private struct MinRow: Identifiable {
        let id = UUID()
-        var locationId: Int?
+        var locationId: String?
        var amount: String
    }

@@ -442,8 +442,8 @@ struct ProductLocationMinView: View {
            ForEach($rows) { $row in
                HStack {
                    Picker("Lagerort", selection: $row.locationId) {
-                        Text("– wählen –").tag(Int?.none)
-                        ForEach(locations) { l in Text(l.name).tag(Int?.some(l.id)) }
+                        Text("– wählen –").tag(String?.none)
+                        ForEach(locations) { l in Text(l.name).tag(String?.some(l.id)) }
                    }
                    TextField("Menge", text: $row.amount)
                        .keyboardType(.decimalPad)
@@ -488,7 +488,7 @@ struct ProductLocationMinView: View {
        busy = true
        defer { busy = false }
        var list: [LocationMinStockIn] = []
-        var gesehen: Set<Int> = []
+        var gesehen: Set<String> = []
        for row in rows {
            guard let loc = row.locationId, !gesehen.contains(loc) else { continue }
            let wert = Double(row.amount.replacingOccurrences(of: ",", with: ".")) ?? 0
--- a/web/src/components/Einzelstuecke.jsx
+++ b/web/src/components/Einzelstuecke.jsx
@@ -100,7 +100,7 @@ export default function Einzelstuecke({ product, locations, shops, isAdmin, onCh
      const cents = centsFrom(addForm.price);
      const created = await api.createItems(product.id, {
        count: Number(addForm.count) || 1,
-        location_id: addForm.location_id === "" ? null : Number(addForm.location_id),
+        location_id: addForm.location_id === "" ? null : addForm.location_id,
        shop_id: shopId,
        acquired_on: addForm.acquired_on || null,
        warranty_until: addForm.warranty_until || null,
@@ -269,7 +269,7 @@ export default function Einzelstuecke({ product, locations, shops, isAdmin, onCh
                <td data-label="Lagerort">
                  {isAdmin ? (
                    <select value={it.location_id ?? ""} style={{ marginTop: 0, minWidth: 120 }}
-                      onChange={(e) => patchItem(it, { location_id: e.target.value === "" ? null : Number(e.target.value) })}>
+                      onChange={(e) => patchItem(it, { location_id: e.target.value === "" ? null : e.target.value })}>
                      <option value="">– ohne –</option>
                      {locations.map((l) => <option key={l.id} value={l.id}>{l.name}</option>)}
                    </select>
--- a/web/src/components/LocationMinStock.jsx
+++ b/web/src/components/LocationMinStock.jsx
@@ -35,7 +35,7 @@ export default function LocationMinStock({ locations, initial = [], unitLabel =
    try {
      const list = rows
        .filter((r) => r.location_id !== "" && Number(r.min_stock) > 0)
-        .map((r) => ({ location_id: Number(r.location_id), min_stock: Number(r.min_stock) }));
+        .map((r) => ({ location_id: r.location_id, min_stock: Number(r.min_stock) }));
      await onSave(list);
      setOk(true);
    } catch (err) {
--- a/web/src/components/ObjektBestand.jsx
+++ b/web/src/components/ObjektBestand.jsx
@@ -56,7 +56,7 @@ export default function ObjektBestand({ product, lots, locations, isAdmin, onCha
        product_id: product.id,
        quantity: menge,
        unit: einheit,
-        location_id: addForm.location_id === "" ? null : Number(addForm.location_id),
+        location_id: addForm.location_id === "" ? null : addForm.location_id,
      });
      setAddForm({ location_id: addForm.location_id, quantity: "" });
      await nachAktion();
@@ -93,8 +93,8 @@ export default function ObjektBestand({ product, lots, locations, isAdmin, onCha
      await api.relocateStock({
        product_id: product.id,
        quantity: menge,
-        from_location_id: move.from === "" ? null : Number(move.from),
-        to_location_id: move.to === "" ? null : Number(move.to),
+        from_location_id: move.from === "" ? null : move.from,
+        to_location_id: move.to === "" ? null : move.to,
      });
      setMove(null);
      toast("Umgelagert.");
@@ -110,7 +110,7 @@ export default function ObjektBestand({ product, lots, locations, isAdmin, onCha
      await api.removeStock({
        product_id: product.id,
        quantity: menge,
-        location_id: remove.location_id === "" ? null : Number(remove.location_id),
+        location_id: remove.location_id === "" ? null : remove.location_id,
        reason: remove.reason,
        note: remove.note || null,
      });
--- a/web/src/pages/CheckIn.jsx
+++ b/web/src/pages/CheckIn.jsx
@@ -237,7 +237,7 @@ export default function CheckIn() {
        best_before:
          (precision === "month" ? fromMonthInput(l.best_before) : l.best_before) || null,
        best_before_precision: precision,
-        location_id: locationId === "" ? null : Number(locationId),
+        location_id: locationId === "" ? null : locationId,
      }));
    if (payloadLines.length === 0) {
      setError("Bitte mindestens eine Menge angeben.");
--- a/web/src/pages/LocationResolve.jsx
+++ b/web/src/pages/LocationResolve.jsx
@@ -26,7 +26,7 @@ export default function LocationResolve() {
    <div>
      <div className="page-head">
        <div>
-          <h1>Lagerort {name || `#${id}`}</h1>
+          <h1>Lagerort {name || id}</h1>
          <div className="sub">
            {error || "Diesen QR-Code in der App scannen (Ort zuordnen), um Einzelstücke hier einzuordnen."}
          </div>
--- a/web/src/pages/Locations.jsx
+++ b/web/src/pages/Locations.jsx
@@ -30,7 +30,7 @@ export default function Locations() {
    e.preventDefault();
    setError(null);
    try {
-      await api.createLocation({ name, parent_id: parentId === "" ? null : Number(parentId) });
+      await api.createLocation({ name, parent_id: parentId === "" ? null : parentId });
      setName("");
      // Übergeordneten Ort absichtlich stehen lassen – beim Anlegen vieler Orte
      // unter demselben Elternteil spart das jedes Mal die Neuauswahl.
@@ -56,7 +56,7 @@ export default function Locations() {
    try {
      await api.updateLocation(editId, {
        name: editName.trim(),
-        parent_id: editParent == null ? null : Number(editParent),
+        parent_id: editParent == null ? null : editParent,
      });
      setEditId(null);
      load();
@@ -141,7 +141,7 @@ export default function Locations() {
            <label className="grow">
              Übergeordneter Lagerort (optional)
              <CategorySelect
-                value={parentId === "" ? null : Number(parentId)}
+                value={parentId === "" ? null : parentId}
                nodes={ordered}
                rootLabel="– keiner (oberste Ebene) –"
                onChange={(id) => setParentId(id == null ? "" : String(id))}