```mermaid
classDiagram
    direction RL

   namespace Geschäftspartner {
       class partner-MeierGmbH
       class partnerDetails-MeierGmbH
       class contact-MeierGmbH
       class person-MeierGmbH
       
       class debitor-MeierGmbH
       class contact-MeierGmbH-Buha
       
       class person-FrankMeier
       class contact-FrankMeier
       class rel-MeierGmbH-FrankMeier

       class person-SabineMeier
       class contact-SabineMeier
       class rel-MeierGmbH-SabineMeier
   }
        
    class partner-MeierGmbH {
        +person
        +contact
        +details
    }
    partner-MeierGmbH o-- person-MeierGmbH
    partner-MeierGmbH o-- contact-MeierGmbH
    partner-MeierGmbH *-- partnerDetails-MeierGmbH

    class partnerDetails-MeierGmbH {
        +registrationOffice
        +registrationNumber
        +birthName
        +dateOfDeath
    }

    class person-MeierGmbH {
        + personType: LEGAL
        + tradeName: Meier GmbH
        + familyName
        + givenName
    }

    class contact-MeierGmbH {
        +postalAddress:     Hauptstraße 5, 22345 Hamburg
        +phoneNumbers:      +49 40 12345-00
        +emailAddresses:    office@meier-gmbh.de
    }

    class debitor-MeierGmbH {
        +Partner    partner
        +Numeric(2) debitorNumberSuffix:    00
        +Contact    billingContact
        +boolean    billable:               true
        +String     vatId:                  ID123456789
        +String     vatCountryCode:         DE
        +boolean    vatBusiness:            true
        +boolean    vatReverseCharge:       false
        +BankAccount refundBankAccount
        +String     defaultPrefix:          mei
    }
    debitor-MeierGmbH o-- partner-MeierGmbH
    debitor-MeierGmbH o-- contact-MeierGmbH-Buha
    
    class contact-MeierGmbH-Buha {
        +postalAddress:     Hauptstraße 5, 22345 Hamburg
        +phoneNumbers:      +49 40 12345-05
        +emailAddresses:    buha@meier-gmbh.de
    }

    class person-FrankMeier {
        + personType: NATURAL
        + tradeName
        + familyName: Meier
        + givenName: Frank
    }

    class contact-FrankMeier {
        +postalAddress
        +phoneNumbers: +49 40 12345-22
        +emailAddresses: sabine.meier@meier-gmbh.de
    }

    class rel-MeierGmbH-FrankMeier {
        +RelType relType REPRESENTATIVE
        +Person relAnchor
        +Person relHolder
        +Contact contact
    }
    rel-MeierGmbH-FrankMeier o-- person-MeierGmbH : relAnchor
    rel-MeierGmbH-FrankMeier o-- person-FrankMeier : relHolder
    rel-MeierGmbH-FrankMeier o-- contact-FrankMeier

    class person-SabineMeier {
        +personType: NATURAL
        +tradeName
        +familyName: Meier
        +givenName: Sabine
    }

    class contact-SabineMeier {
        +postalAddress
        +phoneNumbers: +49 40 12345-22
        +emailAddresses: sabine.meier@meier-gmbh.de
    }

    class rel-MeierGmbH-SabineMeier {
        +RelType relType OPERATIONAL
        +Person relAnchor
        +Person relHolder
        +Contact contact
    }
    rel-MeierGmbH-SabineMeier o-- person-MeierGmbH : relAnchor
    rel-MeierGmbH-SabineMeier o-- person-SabineMeier : relHolder
    rel-MeierGmbH-SabineMeier o-- contact-SabineMeier

    namespace Enums {

        class RelType {
            <<enumeration>>
            UNKNOWN
            REPRESENTATIVE
            ACCOUNTING
            OPERATIONS
        }

        class PersonType {
            <<enumeration>>
            UNKNOWN
            NATURAL
            LEGAL
            SOLE_REPRESENTATION
            JOINT_REPRESENTATION
        }

    }
```

```mermaid
classDiagram
    classA --|> classB : Inheritance
    classC --* classD : Composition
    classE --o classF : Aggregation
    classG --> classH : Association
    classI -- classJ : Link(Solid)
    classK ..> classL : Dependency
    classM ..|> classN : Realization
    classO .. classP : Link(Dashed)
```