Default- and Missing-Value Handling

Change History

Id Subject Date
Latest Commit KBLFRM-1190: Moved content from Recommendation to Impl.-Guidelines and added docs for mandatory doubles. 2024-03-14
KBLFRM-1191  Extracted information from PSI recommendation and extended it where necesseray. 2024-03-14
KBLFRM-1190  Added section for handling of 'double' values. 2024-03-14

For various reasons, there may be attributes of entities where no value can be exported, or a special semantics is required. The cases are:

  • The information is not supported by the system / process. So, it is never available for this system / process.
  • The information is supported by the system; however, the value is not defined by the user.
  • The information is explicitly defined as “arbitrary” for the use case (e.g. the part version in a bill of material or a compatibility statement).

All cases might exist for mandatory attributes as well as for optional attributes. Due to the design, numerical values in the VEC and its high level of optionality the following definition of special values should be only relevant for xs:string-Attributes:

Mandatory Attribute Optional Attribute
Unsupported <tag>/NULL</tag> omitted tag
Undefined <tag></tag> <tag></tag>
Arbitrary <tag>/ANY</tag> <tag>/ANY</tag>
  • /NULL & /ANY means, that the attributes with the name “tag” in the VEC receive these values.
  • <tag></tag> means, that an attribute with the name “tag” and an undefined value is represented in the VEC as an existing XML element with no value (no contained text() node).
  • omitted tag: means the element tag for the attribute is not present in the VEC
The datatype xs:double has less flexibility of allowed values. If the equivalent of /NULL is required for xs:double valued attributes, NaN shall be used. The other cases for xs:string-Attributes, mentioned above, are not supported by xs:double-Attributes.