[ADD]: Addition of delete many

[AbhijithGanesh]

Summary

Delete the row(s) on db at the same time returning the data of deleted row(s).

Motivation

Various other delete methods, this method is a good method to implement as it makes the ORM more complete.

Additional Information

Rough idea is that we need two new methods in DeleteMany, https://github.com/SeaQL/sea-orm/blob/af235168db3a675e889974a34799890350be00e4/src/executor/delete.rs#L34-L46, namely one & all which return single model & array of models respectively. For database support RETURNING, https://docs.rs/sea-orm/0.6.0/sea_orm/query/trait.ConnectionTrait.html#method.support_returning, it will use RETURNING syntax on delete statement to get the data of deleted models.

[AbhijithGanesh]

@billy1624 can you please assign this to me?

[billy1624]

Assigned! :P

[billy1624]

Hey @AbhijithGanesh,

Rough idea is that we need two new methods in DeleteMany, namely one & all which return single model & array of models respectively.

sea-orm/src/executor/delete.rs

Lines 34 to 46 in af23516

	impl<'a, E> DeleteMany<E>
	where
	E: EntityTrait,
	{
	/// Execute a DELETE operation on many ActiveModels
	pub fn exec<C>(self, db: &'a C) -> impl Future<Output = Result<DeleteResult, DbErr>> + '_
	where
	C: ConnectionTrait,
	{
	// so that self is dropped before entering await
	exec_delete_only(self.query, db)
	}
	}

For database support RETURNING, it will use RETURNING syntax on delete statement to get the data of deleted models.

[tyt2y3]

I think this has partially been solved by 008f844

although for delete one, it's possible that we pass-through the primary key (like insert) and do a second query if backend does not support returning