Reimplement nested upsert.
@@ -109,6 +109,8 @@ fn handle_many_to_many(
/// ```
/// The ID of the child is injected into the parent operation. This can be more than one record getting updated.
///
+/// ---
+///
/// In case the relation is inline in the child, we can have the parent execute first,
/// then do an update on the child to insert the parent ID into the inline relation field.
/// ```text
