In a formal data dictionary, there is often a requirement that no two data elements may have the same name, to allow the data element name to become an identifier, though some data dictionaries may provide ways to qualify the name in some way, for example by the application system or other context in which it occurs.
The data element name typically conforms to ISO/IEC 11179 metadata registry naming conventions and has at least three parts: Many standards require the use of Upper camel case to differentiate the components of a data element name.
This is the standard used by ebXML, GJXDM and NIEM.
Users frequently encounter ISO/IEC 11179 when they are exposed to XML Data Element names that have a multi-part Camel Case format: The specification also includes normative documentation in appendices.
In this case the optional qualifier is not used, in spite of being implicit in the data element name.