code: private String createViewDisallowedMessage(String viewName, String singleTableName) {
          boolean singleTable = (singleTableName != null);
          return String.format(
                  "Unable to create %sview %s %sbecause the view definition uses operations that cannot always be applied if %s.",
                  (singleTable
                          ? "single table "
                          : "multi-table "),
                  viewName,
                  (singleTable
                          ? String.format("on table %s ", singleTableName)
                          : ""),
                  (singleTable
                          ? "the table already contains data"
                          : "none of the source tables are empty"));
      }
docs: Return an error message asserting that we cannot create a view
  with a given name.
  
  @param viewName The name of the view we are refusing to create.
  @param singleTableName The name of the source table if there is
  one source table.  If there are multiple
  tables this should be null.  This only
  affects the wording of the error message.
  @return