API version: dev

---

# Transfer of ownership

In order to transfer ownership over a specific element and its children, two things must happen:

- The new owner receives ownership.
- The old owner removes their ownership.

## Initial state

The current owner has ownership over the element, while the new owner has not:

```json graph-example
[
  {"id":"ownerOld","type":"User","data":{"name":"Old owner"}},
  {"id":"ownerNew","type":"User","data":{"name":"New owner"}},
  {"id":"element","type":"Data","data":{"name":"Element"}},
  {"id":"ownsOld","type":"OWNS","start":"ownerOld","end":"element"}
]
```

## Adding new owners

The new owner is granted explicit ownership of the element by creating an `OWNS`-relation:

```bash
curl \
  -H 'Authorization: Bearer secret-token:PIPeJGUt7c00ENn8a5uDlc' \
  -H 'Content-Type: application/json' \
  -d '{
        "type": "OWNS",
        "start": "<uuid of new owner>",
        "end": "<uuid of element"
      }' \
  https://api.example.com/
```

```json graph-example
[
  {"id":"ownerOld","type":"User","data":{"name":"Old owner"}},
  {"id":"ownerNew","type":"User","data":{"name":"New owner"}},
  {"id":"element","type":"Data","data":{"name":"Element"}},
  {"id":"ownsOld","type":"OWNS","start":"ownerOld","end":"element"},
  {"id":"ownsNew","type":"OWNS","start":"ownerNew","end":"element","data":{}}
]
```

## Removing old owners

First find out which ownership claims exist:

```bash
curl \
  -H 'Authorization: Bearer secret-token:PIPeJGUt7c00ENn8a5uDlc' \
  'https://api.example.com/<uuid of element>/parents'
```

```bash
{
  "type": "_PartialCollection",
  "id": "/<uuid of element>/parents",
  "totalNodes": 1,
  "links": {
    "first": "/<uuid of element>/parents",
    "previous": null,
    "next": null,
    "last": "/<uuid of element>/parents"
  },
  "nodes": [
    {
      "type": "User",
      "id": "<uuid of old user>",
      "data": {
        "created": "2025-09-27T10:26:49+00:00",
        "updated": "2025-09-27T10:26:49+00:00"
      }
    },
    {
      "type": "User",
      "id": "<uuid of new user>",
      "data": {
        "created": "2026-07-27T10:26:49+00:00",
        "updated": "2026-07-27T10:26:49+00:00"
      }
    }
  ],
  "relations": [
    {
      "type": "OWNS",
      "id": "0c4cabca-a519-4ace-9b7b-2f4d57c31259",
      "start": "<uuid of old owner>",
      "end": "<uuid of element>",
      "data": {
        "created": "2025-09-27T10:26:49+00:00",
        "updated": "2025-09-27T10:26:49+00:00"
      }
    },
    {
      "type": "OWNS",
      "id": "0d1817ab-9c6e-4052-8a1c-6913163cfff3",
      "start": "<uuid of new owner>",
      "end": "<uuid of element>",
      "data": {
        "created": "2026-07-27T10:26:49+00:00",
        "updated": "2026-07-27T10:26:49+00:00"
      }
    }
  ]
}
```

You then look for the `uuid` of the `OWNS`-relation between the old owner and the element, in this case it is
`0c4cabca-a519-4ace-9b7b-2f4d57c31259`.

This relation can then be deleted:

```bash
curl -X DELETE \
  -H 'Authorization: Bearer secret-token:PIPeJGUt7c00ENn8a5uDlc' \
  https://api.example.com/0c4cabca-a519-4ace-9b7b-2f4d57c31259
```

The graph will then look like this:

```json graph-example
[
  {"id":"ownerOld","type":"User","data":{"name":"Old owner"}},
  {"id":"ownerNew","type":"User","data":{"name":"New owner"}},
  {"id":"element","type":"Data","data":{"name":"Element"}},
  {"id":"ownsNew","type":"OWNS","start":"ownerNew","end":"element"}
]
```

And the old owner can no longer access the element - unless he has access to it through alternative paths.

## Notes

- In order to remove ownership claims, you need to have enough permissions to a) read the ownership claim in the first
  place and b) have write permissions to delete it.
- If you want to transfer ownership from you to someone else, you have to remove your claim _after_ you transferred it.
  Otherwise, you do not have enough permissions to complete the transfer.
- Removing the last owner from an element can result in dangling sub-graphs, which are no longer accessible by any user.
  These elements can only be rescued by interacting with the underlying database directly, i.e. adding new `OWNS`-
  relations with all the required data (id). Only administrators can do this, but even then this approach is not
  recommended.
- Removal of an `OWNS`-relation does not necessarily mean that one user can no longer access the element, as there might
  be alternative paths to access the element:
  - Access through different groups, parallel `OWNS`-relations etc.
  - Limited access through non-ownership-permissions, e.g. `HAS_READ_ACCESS`.
  - Limited access through `CREATED`-relations.

---

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