code: @Override
      public void build(Concept parent) throws OntologyBuildException {
          if (!this.skipProviderHierarchy) {
              try {
                  root = this.metadata.getOrCreateHardCodedFolder("Provider");
                  root.setFactTableColumn("provider_id");
                  root.setTableName("provider_dimension");
                  root.setColumnName("provider_path");
                  if (parent != null) {
                      root.setAlreadyLoaded(parent.isAlreadyLoaded());
                      parent.add(root);
                  }
                  alpha = createAlphaCategoryConcepts();
              } catch (InvalidConceptCodeException ex) {
                  throw new OntologyBuildException("Could not build provider concept tree", ex);
              }
          }
      }
docs: Create a hierarchy of providers organized by first letter of their full
  name.
  
  @return the root of the hierarchy.
  
  @throws OntologyBuildException if an error occurs building the hierarchy.