relationships - how to add table or layer to existing hosted feature layer

[mikAMD]

I'm trying to create a relationship between a hosted feature layer and a table (flat csv, no spatial data). Both are up on arcgis online.

I have tried with the REST API to add a relationship and I get a success response. However, when I go check the parameters page of the feature service, I get an empty "relationships" key.

It's written here that it is possible to add a relationship but both items have to be within the same service. So how can I add a table to an existing hosted feature layer? I wish to do this exclusively with the REST API, without opening arcgis pro.

Thanks!

[mikAMD · Accepted solution]

I've found this thread which concerns my same exact question/problem with this answer. I haven't tested it yet, which is what I'll do now, but I assume that it solves my issue.