General extension rules¶

DATEX II models can be extended using extensions. The following conditions must be kept in mind:

• DATEX can be extended with application specific extensions.
• Extensions are recommended to be done in the UML model. Users are strongly discouraged to manually edit the generated schemas.
• A level A model can be extended and will then become a Level B if the Level B extensions rules are respected. If not, the model will become a Level C model.

On this level only the extending of enumerations is described. If you want to consult the whole guide click here

Extending Enumerations¶

• To extend an enumeration, create a new enumeration by dragging a D2Enumeration from the resources tab, to the extension package or a diagram in the extension package. To indicate that an enumeration is extending an existing element, the D2LevelBExtension UML construct shall be used.
• The new enumeration extends an existing(Level A) enumeration. In the following example the ExtendedPublicEventTypeEnum extends the existing PublicEventTypeEnum from Level A.

• To new enumerations it’s allowed to add new enumeration literals.