Когда отрабатывает функция функционального доменного индекса : Oracle

  IF (indexctx.IndexInfo IS NOT NULL) THEN
    storage_tab_name := indexctx.IndexInfo.INDEXSCHEMA || '.' ||
                        indexctx.IndexInfo.INDEXNAME || '_STORAGE_TAB';
    IF (scanctx IS NULL) THEN
/* This is the first call. Open a cursor for future calls.
   First, do some error checking
*/
      IF (lower_pos > upper_pos) THEN
        RAISE_APPLICATION_ERROR(-20101,
          'Upper Position must be greater than or equal to Lower Position');
      END IF;
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