I am not sure if this issue is your responsibility or DBIx::Class's, but here it is:

I have changed DB from MySQL to MariaDB. I am also using DBIx::Class. So, I am using DBIx::Class::Storage::DBI::MariaDB you kindly provided in order to take care of the missing loader for MariaDB.

I have noticed that in the produced schema files with MySQL loader the primary key is set explicitly with this: __PACKAGE__->set_primary_key("id");. But with MariaDB loader the said declaration is missing and now I have:

__PACKAGE__->add_unique_constraint(
  "PRIMARY",

    [
      "id",
    ],
);

The above perhaps are equivalent but DBIx::Class complains with:

Error:  {UNKNOWN}: DBIx::Class::ResultSource::_pri_cols_or_die(): Operation requires a primary key to be declared on 'MyApp::Schema::XYZ' via set_primary_key ...

As if there is no primary key set.

This error disappears when I explicitly add a __PACKAGE__->set_primary_key("id"); in the custom-code section of the schema file.

EDIT after 30mins: Furthermore the primary key set via the constraint is not auto-incremented even if my SQL is something like:

CREATE TABLE IF NOT EXISTS XYZ (
        id mediumint unsigned NOT NULL primary key auto_increment,
        ...
) AUTO_INCREMENT=1;

See - https://metacpan.org/release/VEESH/SQL-Translator-1.63/source/lib/SQL/Translator/Producer/MySQL.pm .. should probably a) test this b) figure out how it would be supported / integrate ?