There has been increasing interest in the standards community about the value and use of conceptual data models to support messaging standards – separating the conceptual business view from the technical implementation artifacts. This article supports this view using UBL as a reference. 

The UBL standard is a coordinated set of XML grammatical components that allows trading partners to unambiguously identify the information in business documents to be exchanged in a particular business context.  But UBL also offers more than this.  

Since its inception in 2002, UBL has taken a data model approach to designing standardized business documents (that can be expressed in XML).  In fact, all UBL document types are made up of components from a common data model we call the Common Library.

Confusion and obfuscation often surround the term data model. In its normal use, it means a model describing the data needed and created by business processes.  As noted in the introduction such models are useful in allowing meaningful discussion between business experts and the technicians building systems to support their requirements.  To achieve this, a data model should be conceptual (not technological) and should focus on the semantics (the meanings and relationships) of the components it describes.

Using a semantic data model to describe the UBL Common Library has proven beneficial in several ways:

1. Business experts can work on the semantics of UBL business processes and their data requirements without needing to know XML technology.  This methodology is based on principles of business data analysis and modeling and uses the ebXML Core Component Technical Specification (ISO 15000-5) for its notation. 
2. The common data model ensures that the common semantics of the components are not lost when they are re-used in different contexts.  This means a UBL Address is always the same component wherever it appears.
3. It is possible to automatically generate from the UBL data models not only XML representations of document types such as XML Schema and RelaxNG but also non-XML representations such as ASN.1. This effectively ‘future-proofs’ UBL from changes in notations and syntaxes. 
4. Because the UBL semantic data model is similar to a relational data model, some user communities also use this data model for their own internal data representations.  Why re-invent common data structures from scratch when UBL has already designed a useful starting point?

Another benefit of a data model approach can be seen in the development of the document types for new business processes.  There is an 80/20 rule emerging suggesting that the 80% of data requirements for most common business processes are now in the UBL 2.1 data model. 

UBL accompanies its semantic data model with detailed textual descriptions, explanations,and examples of each of its specified functions and messages, as well as clear rules for extension and a number of subsets and tool resources such as localization dictionaries in Chinese, Danish, German, Italian, Japanese, Korean, Spanish and Turkish. This enables communities to create explicit extensions that are locally profiled for their context of use.

To put some reality into this, the foundation of the UBL semantic data model can be outlined using the diagram below.  For more detailed analysis UML, HTML and spreadsheet versions are provided.  

Having a foundation based on a common semantic data model provides long term sustainability for the growing number of communities who are implementing solutions based on UBL.  

For more details:

OASIS UBL 2.1 specification Appendix C The UBL 2.1 Data Model (http://docs.oasis-open.org/ubl/os-UBL-2.1/UBL-2.1.html#A-THE-UBL-2.1-DAT...)