code: func TypeToStr(tp byte, cs string) (r string) {
  	ts := type2Str[tp]
  	if cs != charset.CharsetBin {
  		return ts
  	}
  	if IsTypeBlob(tp) {
  		ts = strings.Replace(ts, "text", "blob", 1)
  	} else if IsTypeChar(tp) {
  		ts = strings.Replace(ts, "char", "binary", 1)
  	}
  	return ts
  }
docs: // TypeToStr converts a field to a string.
  // It is used for converting Text to Blob,
  // or converting Char to Binary.
  // Args:
  //	tp: type enum
  //	cs: charset