erDiagram
    ingredient {
        int id PK
        varchar name UK
        varchar unit
        int stock_quantity
        int stock_capacity
        smallint pack_size
        smallint low_stock_pct
        smallint critical_stock_pct
        tinyint is_active
    }
    product_ingredient {
        int product_id PK,FK
        int ingredient_id PK,FK
        smallint quantity_normal
        smallint quantity_maxi
        tinyint is_removable
        tinyint is_addable
        int extra_price_cents
    }
    allergen {
        int id PK
        varchar code UK
        varchar name
    }
    ingredient_allergen {
        int ingredient_id PK,FK
        int allergen_id PK,FK
    }
    stock_movement {
        int id PK
        int ingredient_id FK
        enum movement_type
        int delta
        int order_id FK
        int user_id FK
        varchar note
    }
    product {
        int id PK
        varchar name
    }
    customer_order {
        int id PK
        varchar order_number
    }
    user {
        int id PK
        varchar email
    }

    product ||--o{ product_ingredient : "product_id (CASCADE)"
    ingredient ||--o{ product_ingredient : "ingredient_id (RESTRICT)"
    ingredient ||--o{ ingredient_allergen : "ingredient_id (CASCADE)"
    allergen ||--o{ ingredient_allergen : "allergen_id (RESTRICT)"
    ingredient ||--o{ stock_movement : "ingredient_id (RESTRICT)"
    customer_order ||--o{ stock_movement : "order_id (SET NULL, nullable)"
    user ||--o{ stock_movement : "user_id (SET NULL, nullable)"