4.11 Object Reference

This package defines mechanisms for data objects to reference one another and external files in the context of an EPC file (Figure 4.11-1).

• The data object reference (DataObjectReference) provides a way for instances of top-level Energistics objects to reference one another by their respective UUIDs.

Examples of usage of data object reference:

• In WITSML, it is used to create the well/wellbore/<object> hierarchy, where <object> can be a log, wellbore geology, or trajectory station.
• In RESQML, it is used to create relationships between earth modeling data objects—faults, horizons, geobodies, grids, properties, etc.—to define models (not just independent objects).

• The EPC external part reference (EpcExternalPartReference) provides a reference from an instance of an XML data object in an EPC file to a system file where the actual data for that object is stored.

Examples of usage of EPC external part reference:

• In RESQML and PRODML-DAS, it’s used to reference HDF5 files that store numerical data and arrays associated with an XML data object.
• Could potentially be used to include a seismic survey in an EPC package; i.e., create an XML data object to identify the survey and then point to a SEG-Y file containing the actual survey data.

For more information, see the Energistics Packaging Conventions (EPC) Specification.

Figure 4.11-1 UML diagram of ObjectReference.