3.2.2 XML Data Objects in an EPC File

XML data objects define the actual data that is being exchanged. These data objects may be from any of the Energistics data-exchange standards. For special rules for using WITSML 1.4.1 data objects with EPC, see 3.2.2.1 Rules for Using WITSML 1.4.1 Data Objects in an EPC file

NOTE: An EPC file may have xml files from multiple versions of the Energistics standards (RESQML, WITSML, and PRODML). For example, an EPC file can contain xml files saved in RESQML v2.0.1 and v2.1.

XML data objects have the following mandatory elements:

• UUID. This is a unique ID scoped to the creator of the package. This means that the ID should be unique for all packages generated by the same creator. The format of the UUID is described in ISO / IEC 9834-8:2008 (which is freely available at http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html ) and IETF RFC 4122. NOTE: For UUIDs, RESQML is case-insensitive.

• Metadata citations group including the title, a human readable identification of the data object. For more information about metadata citations in Energistics standards, see the Energy Industry Profile of ISO 19115-1 (EIP) (link to this document available in Section 1.4 Resource Set for EPC).

NOTE: A data object may optionally NOT contain any data. For example, RESQML (V2.0 or higher) allows reference to data objects to establish or maintain accurate context for a model, but the actual data may have been transferred previously or may be transferred in the future.