private static Optional<String> firstMatchingGroup(Pattern p, String s) {
    Matcher m = p.matcher(s);
    if (m.matches()) {
      return Optional.of(m.group(1));
    }
    else {
      return Optional.absent();
    }
  }
Strips out quotation characters ('"[]) and schema prefixes from identifiers
(table / columns / constraint names)
@param input an identifier
@return the important part of the identifier
ambari-server/src/test/java/org/apache/ambari/server/orm/db/DDLTestUtils.java