On conflict do nothing for MySQL

[tyt2y3]

Continuing #680 in trying to solve SeaQL/sea-orm#1790

However I want to gather comments here whether INSERT IGNORE is a good substitution for ON CONFLICT DO NOTHING

It seems a better way would be to do ON DUPLICATE KEY UPDATE id=id, however this requires us to add an API to the frontend to allow users to pass in the primary key.

https://stackoverflow.com/questions/4596390/insert-on-duplicate-key-do-nothing

[tyt2y3]

I think INSERT IGNORE is an inappropriate solution to ON CONFLICT DO NOTHING.

I think we should add a special method for MySQL that would result in ON DUPLICATE KEY UPDATE id=id.

https://github.com/SeaQL/sea-query/blob/a784868fd7bdcd690529fcbb0874b2c4dbb18d16/src/query/on_conflict.rs#L152C7-L152C7

In SeaORM we have the PK information.

May be OnConflictAction::DoNothing can be extended to DoNothing(Option<DynIden>) to hold the PK? Or is there a better way to transparently handle this?