How to make a cross reference to another object in Weaviate?

Question

How do I make a cross-reference to another thing in Weaviate?

I tried the code below, but I get an error message (also below)

weaviateObj = {
  "class": "Article",
  "schema": {
     "articleTitle": articlemeta.title,
     "publisherId": articlemeta.publisherId,
     "digitalObjectIdentifier": articlemeta.digitalObjectIdentifier,
     "publishedInJournal": {
          "beacon" : WEAVIATE_URL + "/v1/things/" + journaluuid
     }
    }
}

r = runREST(WEAVIATE_URL + "/v1/things", weaviateObj, 0, "POST")

ERROR:

{
    "error": [
        {
            "message": "invalid thing: invalid cref: reference must be an array, but got a map: map[string]interface {}{\"beacon\":\"http://localhost:8080/v1/things/7d60395e-db76-4401-9994-692ce0f5b10d\"}"
        }
    ]
}

Answer 1

The answer can be found in the error message;

invalid cref: reference must be an array, but got a map: map[string]interface {}

You are sending a map[string] like this:

"publishedInJournal": {
     "beacon" : WEAVIATE_URL + "/v1/things/" + journaluuid
}

But it should be an array:

"publishedInJournal": [{
     "beacon" : WEAVIATE_URL + "/v1/things/" + journaluuid
}]

PS:
Also, not sure what WEAVIATE_URL reffers to, but make sure the syntax is: weaviate://localhost/things/ + journaluuid