@startuml

class Items {
    +item : item[]
}
Items +-- item
class item {
    +productName : string
    +quantity : positiveInteger
    +USPrice : decimal
    +comment : comment
    +shipDate : date
    +partNum : string
}
class PurchaseOrderType {
    +shipTo : USAddress
    +billTo : USAddress
    +comment : comment
    +items : Items
    +orderDate : date
}
class USAddress {
    +name : string
    +street : string
    +city : string
    +state : string
    +zip : decimal
    +country : NMTOKEN
}
class comment {
    +value : string
}
class purchaseOrder {
}
purchaseOrder *- PurchaseOrderType

@enduml