VML Processing Widget

Summary

One day soon, this page will document the VML Processing Widget. This an ANT-scripted process that:

• consumes proposals for change expressed in the HL7 Vocabulary Maintenance Language (VML),

• splits these proposals into two source streams targeted at the Access repository in which the HL7 Vocabulary content is stored::
  • an SQL update stream for updating files of properties assigned to vocabulary objects, and

  • an XML stream processed in Java to update the primary Access tables

  together, these streams update the vocabulary content stored in the Access repository,

• uses a Java process to "clean up" the Access content,

• invokes RoseTree to express the complete vocabulary content in HL7 Model Interchange Format (MIF), and

• combines this MIF content from the Access repository with an externally maintained MiF extension file to arrive at a final, complete expression of HL7's vocabulary in MIF.

Background - Management of HL7 Vocabulary Content

In brief, the HL7 Vocabulary Content:

• Is published and releases as a formal expression of the content in Model Interchange Format (MIF)files; This format:
  • Documents the data that define each of the artifacts (Concept Domains, Code Systems, Value Sets, etc.)

  • Documents the relationships between the artifacts (such as bindings);

  • Provides a vehicle for using XML X-path logic to query and/or analyze the content;

  • Provides the source for transforms used to publish the content in HL7 Ballots and Normative Editions.

• Is archived and persisted two complimentary forms:
  • an Access data base, designed over 13 years ago, that serves as the "repositiry" for this content; plus

  • “Extensions files,” represented in MIF format, that primarily document those Value Sets that are defined against external code systems) expressed in MIF

• Vocabulary Content is updated through the Vocabulary_and_RIM_Harmonization_Process, the results of which drive updates to the Repository and/or extension files.

Prior to the development of this widget, the means for processing updates to the HL7 Vocabulary Content involved:

• Creating update files expressed in the HL7 Vocabulary Maintenance Language (VML) files.

• "Posting the data in these files to the repository database using the Java-encoded procedures compiled as “VocMaint_and_dependencies.jar”. Weaknesses of this process include:
  • Some updates require manual changes (table/row updates) in Access – but only when VML cannot be used. This requirement arose primarily when it was necessary to update concept properties and “object properties” on Concept Domains and Value Sets

  • The original VML schema encapsulates “descriptive markup” (html formatting of descriptions), such as the definition of a concept or the description of a value set's content and purpose)in a CDATA wrapper. This encapsulation precluded validation of the markup prior to its being posted to the data base with the too-frequent requirement to cretae a subsequent correction update.

• Once the content was posted to the database, the definitive “coremif” was assembled from the Access data by RoseTree, with the “Extensions” merged in by transform.