Drop and redefine predicate in schema

[MichelDiz]

@tron

but in my case I only have one to migrate

You can export you data, and edit your schema as one to one before bulkload it. Or use Upsert block to migrate the relation to a TMP edge and after that delete the one to many, fix that in the schema and do a second migration. That is hard, so the best way is exporting an reimporting.

@tron

…but now all Token.singlePerson edges reference the same Token.person (instead of each referencing its own).

Yep, that’s a know issue. See FOREACH func in DQL (loops in Bulk Upsert)

@tron

Is there a way to do a bulk upsert like this in a single transaction, or do I have to run a separate upsert for each token?

Today you have to do the migration per entity. If you do a Bulk upsert in that case, it will mess up the relations. You have to send several Upserts with a relation 1:1.

@tron

If I must run an upsert for each token, can I do them all in one transaction, or do I need a separate transaction for each upsert?

Not sure, you will have to do a loop for each entity and concat them - would be hard to do. So, as you know that there is only a single relation there, the best is export your data, fix the schema and reimport. Bulk upserts won’t work well for your case.