Edges

Edges are used in graphs to link nodes together. They are documents with two additional system attributes that you set, a _from and a _to attribute. They need to be stored in edge collections.

Together with node documents stored in document collections (also called node collections or vertex collections in this context), edges form graphs.

Example

• An edge collection stores the information that a company’s reception is a sub-unit to the services unit and the services unit is sub-unit to the CEO. You would express this relationship with the _from and _to attributes.
• A node collection stores all the properties about the reception, for example, that 20 people are working there, the room number, and so on.
• The _from attribute of an edge is the document ID of the linked node (incoming relation).
• The _to attribute of an edge is the document ID of the linked node (outgoing relation).

Edges API

Edges are normal documents but additionally have a _from and a _to attribute that you need to set. You can update the _from and _to attributes like any other document attribute using the Documents API.

For methods you can call on edge collections, see the edge document methods of the collection object.