diff --git a/erd.dbml b/erd.dbml
index 1f3e3f8..0f71f4e 100644
--- a/erd.dbml
+++ b/erd.dbml
@@ -1,61 +1,79 @@
-// Use DBML to define your database structure
-// Docs: https://dbml.dbdiagram.io/docs
+// https://dbdiagram.io/d/
+// Kraut&Rübel ERD
 
-Table Kunde {
-  KundenNr integer [primary key]
-  Vorname string
-  Nachname string
-  Strasse string
-  Geburstdatum timestamp
-  HausNr string
-  PLZ integer
-  Email string
-  Telefon integer
-  Ort string
+Table Customer {
+  id string [primary key]
+  first_name string
+  last_name string
+  street string
+  birth_date timestamp
+  house_number string
+  postal_code integer
+  email string
+  phone integer
+  city string
 }
 
-Table Bestellung {
-  BestellNr integer [primary key]
-  KundenNr integer
-  Rechnungsbetrag integer
-  Bestelldatum timestamp
+Table Order {
+  id string [primary key]
+  customer Customer
+  invoice_amount integer
+  order_date timestamp
 }
 
-Table Zutat {
-  ZutatenNr integer [primary key]
-  Bezeichnung string
-  Bestand integer
-  Nettopreis integer
-  Einheit string
-  Kohlenhydrate integer
-  Kalorien integer
-  Protein integer
+Table Ingredient {
+  id string [primary key]
+  designation string
+  stock integer
+  net_price integer
+  unit string
+  carbonhydrates integer
+  calories integer
+  protein integer
 }
 
-Table Lieferant {
-  LieferantenNr integer [primary key]
-  Ort string
-  Strasse string
-  Email string
-  Telefon string
-  Liferantenname string
-  HausNr string
-  PLZ integer
+Table Supplier {
+  id string [primary key]
+  city string
+  street string
+  email string
+  phone string
+  supplier_name string
+  house_number string
+  postal_code integer
 }
 
-Table Lieferant_contains_Zutaten {
-  LieferantenNr integer [primary key]
-  ZutatenNr integer [primary key]
+Table Recipe {
+  id string [primary key]
+  preperation_time integer
+  name string
+  description string
+  instructions string
 }
 
-Table Bestellung_contains_Zutaten {
-  BestellNr integer [primary key]
-  ZutatenNr integer [primary key]
-  Menge integer
+Table RecipeContainsIngredients {
+  recipe string [primary key]
+  ingredient string [primary key]
+  amount integer
 }
 
-Ref: Bestellung.KundenNr > Kunde.KundenNr
-Ref: Lieferant_contains_Zutaten.LieferantenNr > Lieferant.LieferantenNr
-Ref: Lieferant_contains_Zutaten.ZutatenNr > Zutat.ZutatenNr
-Ref: Bestellung_contains_Zutaten.BestellNr > Bestellung.BestellNr
-Ref: Bestellung_contains_Zutaten.ZutatenNr > Zutat.ZutatenNr
+Table SupplierContainsIngredients {
+  supplier string [primary key]
+  ingredient string [primary key]
+  delivery_cost integer
+  delivery_time integer
+}
+
+Table OrderContainsIngredients {
+  order string [primary key]
+  ingredient string [primary key]
+  quantity integer
+}
+
+Ref: Order.customer > Customer.id
+Ref: SupplierContainsIngredients.supplier > Supplier.id
+Ref: SupplierContainsIngredients.ingredient > Ingredient.id
+Ref: OrderContainsIngredients.order > Order.id
+Ref: OrderContainsIngredients.ingredient > Ingredient.id
+Ref: RecipeContainsIngredients.recipe > Recipe.id
+Ref: RecipeContainsIngredients.ingredient > Ingredient.id
diff --git a/lib/datatypes.py b/lib/datatypes.py
index 2c2e931..06d62d7 100644
--- a/lib/datatypes.py
+++ b/lib/datatypes.py
@@ -3,7 +3,7 @@ from dataclasses import dataclass, asdict
 
 @dataclass
 class Customer:
-    customer_id: int
+    id: str
     first_name: str
     last_name: str
     street: str
@@ -20,8 +20,8 @@ class Customer:
 
 @dataclass
 class Order:
-    order_id: int
-    customer: Customer
+    id: str
+    customer: Customer.id
     invoice_amount: int
     order_date: str  # Assuming timestamp as a string for simplicity
 
@@ -31,7 +31,7 @@ class Order:
 
 @dataclass
 class Ingredient:
-    ingredient_id: int
+    id: str
     designation: str
     stock: int
     net_price: int
@@ -46,7 +46,7 @@ class Ingredient:
 
 @dataclass
 class Supplier:
-    supplier_id: int
+    id: str
     city: str
     street: str
     email: str
@@ -60,7 +60,7 @@ class Supplier:
 
 @dataclass
 class Recipe:
-    recipe_id: int
+    id: str
     preperation_time: int
     name: str
     description: str
@@ -70,15 +70,15 @@ class Recipe:
         return {k: str(v) for k, v in asdict(self).items()}
 
 @dataclass
-class SupplierContainsIngredients:
-    recipe: Recipe
-    ingredient: Ingredient
+class RecipeContainsIngredients:
+    recipe: Recipe.id
+    ingredient: Ingredient.id
     amount: int
 
 @dataclass
 class SupplierContainsIngredients:
-    supplier: Supplier
-    ingredient: Ingredient
+    supplier: Supplier.id
+    ingredient: Ingredient.id
     delivery_cost: int
     delivery_time: int
 
@@ -88,8 +88,8 @@ class SupplierContainsIngredients:
 
 @dataclass
 class OrderContainsIngredients:
-    order: Order
-    ingredient: Ingredient
+    order: Order.id
+    ingredient: Ingredient.id
     quantity: int
 
     def dict(self):