fix datatypes, add poster image

README.md

@@ -1 +1,3 @@
 # LF5 Database Project
+
+![img](./poster/dbms.png)

erd.dbml

@@ -16,7 +16,7 @@ Table Customer {
 
 Table Order {
   id string [primary key]
-  customer Customer
+  customer_id string
   invoice_amount integer
   order_date timestamp
 }
@@ -70,7 +70,7 @@ Table OrderContainsIngredients {
   quantity integer
 }
 
-Ref: Order.customer > Customer.id
+Ref: Order.customer_id > Customer.id
 Ref: SupplierContainsIngredients.supplier > Supplier.id
 Ref: SupplierContainsIngredients.ingredient > Ingredient.id
 Ref: OrderContainsIngredients.order > Order.id

lib/datatypes.py

@@ -21,7 +21,7 @@ class Customer:
 @dataclass
 class Order:
     id: str
-    customer: Customer.id
+    customer_id: Customer.id
     invoice_amount: int
     order_date: str  # Assuming timestamp as a string for simplicity