... discussion on character_set_system  and why it is utf8mb3...

....

bar Oct 13th, 2021 at 4:23 PM

@wlad yes, it's hard-coded. I think the biggest problem is to implement table-name-to-file-name encoding for non-BMP characters. Should be doable but needs some time.

5 replies

wlad  3 months ago

so, a surrogate pair won't do? like, @d801@dc37

bar  3 months ago

for characters that do not have lower/upper variants, it will do.

bar  3 months ago

It will actually do for characters that have lower/upper variants as well.

bar  3 months ago

Thanks for the good idea.

PlaneN  Code Range    Abbr      Name

------  ------------  ----      --------------------------------------

0       0000-FFFF     BMP       Basic Multilingual Plane

1       10000-1FFFF   SMP       Supplementary Multilingual Plane

2       20000-2FFFF   SIP       Supplementary Ideographic Plane

3       30000-3FFFF   TIP       Tertiary Ideographic Plane

4-13    40000-DFFFF   ---       unassigned

14      E0000-EFFFF   SSP       Supplementary Special-purpose Plane

15-16   F0000-10FFFF  SPUA-A/B  Supplementary Private Use Area planes

CREATE OR REPLACE VIEW v1 AS

SELECT

  seq,

  char(seq using utf32) collate utf32_uca1400_ai_ci AS ch

FROM seq_1_to_1114111;

SELECT

  ch,

  hex(ch) AS cu,

  upper(ch) AS u,

  hex(upper(ch)) AS uc,

  upper(lower(ch)) u2,

  hex(upper(lower(ch))) AS u2c

FROM v1

WHERE upper(ch) collate utf32_bin<>upper(lower(ch)) collate utf32_bin;

+------+----------+------+----------+------+----------+

| ch   | cu       | u    | uc       | u2   | u2c      |

+------+----------+------+----------+------+----------+

| İ    | 00000130 | İ    | 00000130 | I    | 00000049 | LATIN CAPITAL LETTER I WITH DOT ABOVE

| ϴ    | 000003F4 | ϴ    | 000003F4 | Θ    | 00000398 | GREEK CAPITAL THETA SYMBOL

| ẞ    | 00001E9E | ẞ    | 00001E9E | ß    | 000000DF | LATIN CAPITAL LETTER SHARP S

| Ω    | 00002126 | Ω    | 00002126 | Ω    | 000003A9 | OHM SIGN

| K    | 0000212A | K    | 0000212A | K    | 0000004B | KELVIN SIGN

| Å    | 0000212B | Å    | 0000212B | Å    | 000000C5 | ANGSTROM SIGN

+------+----------+------+----------+------+----------+