Under terms of MDEV 27490 we'll add support for non-BMP identifiers
and upgrade casefolding information to Unicode version 14.0.0.
In Unicode-14.0.0 conversion to lower and upper cases can increase octet length
of the string, so conversion won't be possible in-place any more.
This patch removes virtual functions performing in-place casefolding:
- my_charset_handler_st::casedn_str()
- my_charset_handler_st::caseup_str()
and fixes the code to use the non-inplace functions instead:
- my_charset_handler_st::casedn()
- my_charset_handler_st::caseup()
Add support of referential constraints directly in column defininions:
create table t1 (id1 int primary key);
create table t2 (id2 int references t1(id1));
Referenced field name can be omitted if equal to foreign field name:
create table t1 (id int primary key);
create table t2 (id int references t1);
Until 10.5 this syntax was understood by the parser but was silently
ignored.
In case of generated columns this syntax is disabled at parser level
by ER_PARSE_ERROR. Note that separate FOREIGN KEY clause for generated
columns is disabled at storage engine level.
