Customer:
  - id (INTEGER)
  - name (VARCHAR)
  - balance (DECIMAL)
  - credit_limit (DECIMAL)
  * Filterable: name, balance, credit_limit
  * Example: 'List customers with credit over 5000'

Item:
  - id (INTEGER)
  - order_id (INTEGER)
  - product_id (INTEGER)
  - quantity (INTEGER)
  - amount (DECIMAL)
  - unit_price (DECIMAL)
  * Filterable: order_id, product_id, unit_price
  * Relationships:
    ↪ relates to Order
    ↪ relates to Product
  * Example: 'Find all items for order 42'

Email:
  - id (INTEGER)
  - message (VARCHAR)
  - customer_id (INTEGER)
  * Relationships:
    ↪ relates to Customer
  * Example: 'Post an message "text" for customer 2 means POST to this resource'

Order:
  - id (INTEGER)
  - notes (VARCHAR)
  - customer_id (INTEGER)
  - CreatedOn (DATE)
  - date_shipped (DATE)
  - amount_total (DECIMAL)
  * Filterable: notes, customer_id, date_shipped, amount_total
  * Relationships:
    ↪ relates to Customer
  * Example: 'Get orders shipped in 2024'

Product:
  - id (INTEGER)
  - name (VARCHAR)
  - unit_price (DECIMAL)
  * Filterable: name, unit_price
  * Example: 'Show products with price over 100'