Perspectives

A Perspective is essentially a local graph database that contain the associations between Expressions.

While Expressions contain "objective data", Perspectives can associate meaning between Expressions by linking them together.

Creating a Perspective

Creating a new Perspective is easy:

const myNotes = ad4m.perspective.add("My private notes");

The returning object will be an instance of PerspectiveProxy – which essentially will work as your database instance.

Adding a Link

Perspectives only consist of a collection of links, which connect three Expression URLs:

Subject: The Expression that you want to store or retrieve information about.
Predicate: Describes the relationship between the subject and the target.
Target: The Expression that is connected to the subject.

const link = {
  subject: "did:key:zQ3shv5VUAbtY5P1jGsPzy7L27FTxeDv2hnhVp9QT3ALNCnQ2",
  predicate: "sioc://likes",
  target: "literal://ad4m",
};
 
myNotes.add(link);

Perspective class definition

Query Links

We can query all links on a PerspectiveProxy using the get function:

const allLinks = await myNotes.get(
  new LinkQuery({ predicate: "sioc://likes" })
);

What you get back will be an array of LinkExpressions:

[
  {
    "author": "did:key:zQ3shv5VUAbtY5P1jGsPzy7L27FTxeDv2hnhVp9QT3ALNCnQ2",
    "timestamp": "2023-06-21T14:47:48.935Z",
    "data": {
      "subject": "did:key:zQ3shv5VUAbtY5P1jGsPzy7L27FTxeDv2hnhVp9QT3ALNCnQ2",
      "predicate": "sioc://likes",
      "target": "literal://ad4m"
    },
    "proof": {
      "key": "#zQ3shNWd4bg67ktTVg9EMnnrsRjhkH6cRNCjRRxfTaTqBniAf",
      "signature": "xxxx"
    }
  }
]

Even though this Perspective is not shared (yet) but just our private, local graph database, we might want to share it as Neighbourhood.

Languages Neighbourhoods