Invoice management requires precise modeling to ensure accurate payments and compliance.

Logical Model Entities

• Invoice: Stores invoice data linked to orders.
• Order: Customer orders containing products.
• Product: Supplied items.
• Customer: Customer data and location.
• Address & Address_Type: Support multiple addresses (billing, shipping, postal).

Relationships

• Use primary keys for unique identification and foreign keys for linking entities.
• Example: Invoice_Item links to Invoice via InvoiceNumber.

Physical Model Considerations

• Denormalization: Preserve historical invoice data (snapshot at creation).
• Tables include:
  • Invoice, Invoice_Item, Customer_Order, Customer, Customer_Address, Address_Type, Address.
• Supports globalization (flexible postcode, region, time zone).

Storage Options

• BLOB/CLOB: Store electronic invoices in the database.
• File System + Metadata: Store files externally and track them in the database.

Best Practices

• Document objects with notes.
• Use version control for evolving models.