How to handle blank nodes & items that do not have names?

[moisbo]

How do you join blank nodes?

TODO: @ptsefton to add some detail to this ticket please.

Example from IDN

[ptsefton]

This is about Embedding - see the JSON-LD spec

Where we have stuff entities like Geometry which is used to locate Place, there is currently a requirement to have an extra stand-alone entity to contain the actual geometry, but the UI makes a special case out of this and embeds the Geometry entity in the Place:

In his example the ID of the coordinates is not really important, it's just there to embed this in the place, we could use a Blank Node for this.

We could generalise this for other kinds of embedding (eg PropertyValue) or Roles as used by the IDN so Properties could have values where the profile says "embed": true -- the embedded entity need not have a name.

Here's an example from the spec -- this uses a # id for the property value but this could be a _: instead:

https://www.researchobject.org/ro-crate/1.1/contextual-entities.html#extra-metadata-such-as-exif

{
      "@id": "pics/2017-06-11%2012.56.14.jpg",
      "@type": ["File", "ImageObject"],
      "contentSize": "5114778",
      "author": {
        "@id": "https://orcid.org/0000-0002-3545-944X"
      },
      "description": "Depicts a fence at a disused motor racing venue with the front part of a slightly out of focus black dog in the foreground.",
      "encodingFormat": "image/jpeg",
      "exifData": [
        {
          "@id": "#2eb90b09-a8b8-4946-805b-8cba077a7137"
        },
        {
          "@id": "#c2521494-9b94-4b23-a713-6b281f540823"
        },
      ]
},
{
      "@id": "#c2521494-9b94-4b23-a713-6b281f540823",
      "@type": "PropertyValue",
      "name": "InternalSerialNumber",
      "value": "4102011002108002"
},

[ptsefton]

So for things marked as embed -- they don't turn into a clickable link, they would be displayed inline like Geometry, and whatever inputs are defined in the profile would show as they do here:

[ptsefton]

AND, we can use this to handle this kind of structure as well. (This is another IDN example)

{
   "@id": "https://data.idnau.org/pid/AAC",
    "@type": [
      "http://www.w3.org/ns/dcat#Resource"
    ],
...
    "http://purl.org/dc/terms/identifier": [
      {
        "@type": "http://www.w3.org/2001/XMLSchema#token",
        "@value": "AAC"
      },
      {
        "@type": "https://data.idnau.org/pid/adaId",
        "@value": "au.edu.anu.ada.ddi.20002-aus"
      }
    ],

We could make the RO-Crate library turn these structures into a flattened structure with blank-node @ids for the embeddings. These would then show up inline in the Crate-O for editing and these TYPES could be included in an IDN profile.

{
   "@id": "https://data.idnau.org/pid/AAC",
    "@type": [
      "http://www.w3.org/ns/dcat#Resource"
    ],
...
    "http://purl.org/dc/terms/identifier": [ { "@id":  "_:1"},  { "@id":  "_:2"}],
    }
      { 
       "@id":  "_:1",
        "@type": "http://www.w3.org/2001/XMLSchema#token",
        "@value": "AAC"
      },
      { 
        "@id":  "_:2",
        "@type": "https://data.idnau.org/pid/adaId",
        "@value": "au.edu.anu.ada.ddi.20002-aus"
      }
    ],