🍟 Comprehensive ERD: McDonald’s Integrated Operations System

(Focused on Order Processing, Customer Experience & Store Operations)

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🔍 Business Context

This Entity-Relationship Diagram models core operations in a McDonald’s store, focusing on:

• Order flow from customer to payment

• Employee roles and store management

• Menu availability and pricing

• Customer loyalty and repeat engagement

• Basic inventory tracking (for food items)

Note: This is not a full enterprise database (e.g., supply chain or HR), but a realistic, scalable foundation for a fast-food POS system.

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📚 Entities & Attributes

Entity	Attributes
Customer	CustomerID (PK), Name, Phone, Email, LoyaltyPoints, MembershipTier (e.g., Bronze, Silver)
Store	StoreID (PK), Name, Location (Address), ManagerID (FK → Employee), OpenHours, TotalSales (monthly)
Employee	EmployeeID (PK), Name, Role (Cashier, Cook, Manager, Supervisor), StoreID (FK), HireDate, ShiftSchedule
MenuItem	MenuItemID (PK), Name, Description, Price, Category (Burger, Drink, Side, Dessert), IsActive, ImageURL
Order	OrderID (PK), OrderTime, Status (Pending → Preparing → Ready → Completed → Cancelled), TotalAmount, StoreID (FK), CustomerID (FK)
OrderItem	OrderItemID (PK), OrderID (FK), MenuItemID (FK), Quantity, LineTotal (auto-calculated)
Payment	PaymentID (PK), Amount, Method (Cash, CreditCard, MobilePay), TransactionID, OrderID (FK), Timestamp
Promotion	PromotionID (PK), Code (e.g., “WELCOME10”), DiscountType (Percentage, Fixed), DiscountValue, ActiveDate, ExpireDate, AppliesTo (e.g., Lunch, AllItems)

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🔗 Relationships (with Cardinalities)

Relationship	Cardinality	Description
Customer → Order	1 → 0..	A customer places multiple orders over time.
Order → OrderItem	1 → 0..	Each order contains zero or more menu items.
Order → Payment	1 → 1	Every completed order has exactly one payment.
Order → Store	1 → 1	Each order is placed at one specific store.
Store → Employee	1 → 0..	A store employs multiple staff (cashiers, cooks, managers).
Store → Order	1 → 0..	A store receives many orders.
MenuItem → OrderItem	1 → 0..	A menu item can appear in multiple orders.
Promotion → Order	0 → 1	A promotion may apply to an order (e.g., “Buy 1 Big Mac, Get 1 Free”).
Employee → Store	1 → 1	Each employee works at one store.

✅ Optional: Add a LoyaltyProgram entity if deeper loyalty logic is needed (e.g., points redemption, rewards).

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🔒 Constraints & Business Rules

• Price must be > 0

• Order status cannot be ‘Completed’ if payment is missing

• Quantity in OrderItem ≥ 1

• Promotions can only be applied if active and within time window

• Customer must be linked to at least one order to earn loyalty points

• Menu items are marked as ‘Inactive’ if out-of-stock or discontinued

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📝 Use Cases (Why This ERD Matters)

Use Case	Benefit
POS System Design	Enables real-time order tracking, payment, and receipt generation
Inventory Alerts	When a menu item is ordered frequently, monitor stock levels
Loyalty Programs	Track point accumulation, offer personalized discounts
Store Analytics	Identify top-selling items, peak hours, popular promotions
Employee Management	Assign roles, track shifts, manage performance

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📂 Output Formats

You can copy and paste any of the following into your documentation, presentation, or database design tools.

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✅ 1. Text-Based ERD (for documentation)

Entities:

- Customer
  - CustomerID (PK)
  - Name
  - Phone
  - Email
  - LoyaltyPoints
  - MembershipTier

- Store
  - StoreID (PK)
  - Name
  - Location
  - ManagerID (FK → Employee)
  - OpenHours
  - MonthlySales

- Employee
  - EmployeeID (PK)
  - Name
  - Role (Cashier, Cook, Manager)
  - StoreID (FK)
  - HireDate

- MenuItem
  - MenuItemID (PK)
  - Name
  - Description
  - Price
  - Category
  - IsActive

- Order
  - OrderID (PK)
  - OrderTime
  - Status (Pending, Preparing, Ready, Completed, Cancelled)
  - CustomerID (FK)
  - StoreID (FK)
  - TotalAmount

- OrderItem
  - OrderItemID (PK)
  - OrderID (FK)
  - MenuItemID (FK)
  - Quantity
  - LineTotal

- Payment
  - PaymentID (PK)
  - Amount
  - Method (Cash, CreditCard, MobilePay)
  - OrderID (FK)
  - Timestamp

- Promotion
  - PromotionID (PK)
  - Code
  - DiscountType
  - DiscountValue
  - ActiveDate
  - ExpireDate
  - AppliesTo

Relationships:
- Customer "1" -- "0..*" Order
- Order "1" -- "0..*" OrderItem
- Order "1" -- "1" Payment
- Order "1" -- "1" Store
- Store "1" -- "0..*" Employee
- MenuItem "1" -- "0..*" OrderItem
- Promotion "0..*" -- "1" Order (conditional on active status)

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✅ 2. Mermaid.js Version (for Markdown, Notion, Obsidian)

erDiagram
    CUSTOMER ||--o{ ORDER : "places"
    STORE ||--o{ ORDER : "serves"
    STORE ||--o{ EMPLOYEE : "employs"
    STORE ||--o{ MENU_ITEM : "sells"
    ORDER ||--o{ ORDER_ITEM : "contains"
    ORDER ||--o{ PAYMENT : "has"
    MENU_ITEM ||--o{ ORDER_ITEM : "appears in"
    PROMOTION ||--o{ ORDER : "applies to"

    CUSTOMER {
        int CustomerID PK
        string Name
        string Phone
        string Email
        int LoyaltyPoints
        string MembershipTier
    }

    STORE {
        int StoreID PK
        string Name
        string Location
        int ManagerID FK
        string OpenHours
        decimal MonthlySales
    }

    EMPLOYEE {
        int EmployeeID PK
        string Name
        string Role
        int StoreID FK
        date HireDate
    }

    MENU_ITEM {
        int MenuItemID PK
        string Name
        string Description
        decimal Price
        string Category
        boolean IsActive
    }

    ORDER {
        int OrderID PK
        datetime OrderTime
        string Status
        int CustomerID FK
        int StoreID FK
        decimal TotalAmount
    }

    ORDER_ITEM {
        int OrderItemID PK
        int OrderID FK
        int MenuItemID FK
        int Quantity
        decimal LineTotal
    }

    PAYMENT {
        int PaymentID PK
        decimal Amount
        string Method
        int OrderID FK
        datetime Timestamp
    }

    PROMOTION {
        int PromotionID PK
        string Code
        string DiscountType
        decimal DiscountValue
        datetime ActiveDate
        datetime ExpireDate
        string AppliesTo
    }

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✅ 3. PlantUML Version 

' McDonald's Order System ERD (PlantUML)

package "McDonald's Operations" {
  entity "Customer" {
    - CustomerID (PK)
    - Name
    - Phone
    - Email
    - LoyaltyPoints
    - MembershipTier
  }

  entity "Store" {
    - StoreID (PK)
    - Name
    - Location
    - ManagerID (FK → Employee)
    - OpenHours
    - MonthlySales
  }

  entity "Employee" {
    - EmployeeID (PK)
    - Name
    - Role (Cashier, Cook, Manager)
    - StoreID (FK → Store)
    - HireDate
  }

  entity "MenuItem" {
    - MenuItemID (PK)
    - Name
    - Description
    - Price
    - Category (Burger, Drink, Side)
    - IsActive
  }

  entity "Order" {
    - OrderID (PK)
    - OrderTime
    - Status (Pending, Preparing, Ready, Completed)
    - CustomerID (FK → Customer)
    - StoreID (FK → Store)
    - TotalAmount
  }

  entity "OrderItem" {
    - OrderItemID (PK)
    - OrderID (FK → Order)
    - MenuItemID (FK → MenuItem)
    - Quantity
    - LineTotal
  }

  entity "Payment" {
    - PaymentID (PK)
    - Amount
    - Method (Cash, CreditCard)
    - OrderID (FK → Order)
    - Timestamp
  }

  entity "Promotion" {
    - PromotionID (PK)
    - Code (e.g., WELCOME10)
    - DiscountType (Percentage, Fixed)
    - DiscountValue
    - ActiveDate
    - ExpireDate
    - AppliesTo
  }

  Customer "1" -- "0..*" Order : "places"
  Order "1" -- "0..*" OrderItem : "contains"
  Order "1" -- "1" Payment : "has"
  Order "1" -- "1" Store : "is placed at"
  Store "1" -- "0..*" Employee : "employs"
  MenuItem "1" -- "0..*" OrderItem : "appears in"
  Promotion "0..*" -- "1" Order : "applies to"
}

 

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🔍 Future Extensions (Optional)

If you’d like to expand this ERD, consider adding:

• Inventory → Tracks stock levels, reorder points, supplier info

• Shift Schedule → Daily shifts, break times, shift assignments

• Supplier → Who supplies ingredients (e.g., “Cheese Supplier”)

• Seasonal Menus → Special promotions (e.g., “Summer BBQ Menu”)

• Geolocation → For delivery or pickup tracking

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🚀 Final Thoughts

This ERD is realistic, scalable, and aligned with McDonald’s operations — it reflects actual POS workflows, employee roles, and customer behavior.

✅ You now have a complete, ready-to-use ERD for a McDonald’s system — whether for a school project, business analysis, or technical design.