https://mariadb.com/kb/en/innodb-system-variables/#innodb_force_primary_key ?

Hi Sergei, did you read my description?

Yes, I did. It's true that innodb_force_primary_key only works for InnoDB. My question was that perhaps innodb_force_primary_key, even if it is not completely universal, still solves your specific problem? In case you only actually needed it for InnoDB in your application, I cannot know that.

It seems that you've edited the description to emphasize that you, indeed, need it for other storage engines. That answers my question, thanks.

serg, one substantial problem with innodb_force_primary_key is that, according to the docs, it is Global scope only: https://mariadb.com/kb/en/innodb-system-variables/#innodb_force_primary_key

That means, I believe, that it should be impossible for one connection/thread to temporarily disable the enforcement of primary keys.

On the other hand sql_require_primary_key can be set at either Global or Session scope, so it can be temporarily disabled by e.g. a management connection which needs to do so: https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_sql_require_primary_key

also, there are requests for MariaDB to add a hidden pk automatically (MDEV-21181 and MDEV-24001). Perhaps there should be an enum system variable with values, like, "error without a pk", "auto-add pk", "do nothing" ?