8 References — lightweight pointers

A reference stores the id of another node on this node. It points one way: it is cheap to store and to set, and the target does not know about it.

Type	Stores	Use for
`Reference<T>`	one `Guid`	"the cover image of this event"
`References<T>`	an ordered `Guid[]`, duplicates kept	"the sponsors of this event, in billing order"

public interface IEvent {
    // ...
    [ReferenceProperty(Indexed = true)]     // Indexed = true is needed to filter or facet on it
    Reference<IMediaAsset> Cover { get; }

    [ReferencesProperty(Indexed = true)]
    References<IOrganizer> Sponsors { get; }
}

On a class, initialise them: public Reference<IMediaAsset> Cover { get; set; } = new();.

Reading and writing a Reference<T>
Reading and writing a References<T> — Get() skips stale targets, such as deleted nodes or nodes of the wrong type, instead of throwing.