Relation types can be arbitrary strings. However, the following built-in relations have special meanings:
| relation type | meaning |
| any | all nodes linked from source node (with any relation type) |
| relations | all relations linked from source node |
| onLinked | notify sink node whenever source node is linked to/from |
| onLinkedFrom | notify sink node whenever source node is linked from |
| onLinkedTo | notify sink node whenever source node is linked to |
| onStore | notify sink node whenever source node's object is updated |
| onEmpty | notify sink node whenever source node's mailbox is empty |
| onFull | notify sink node whenever source node's mailbox is full |
Examples
After these operations:
PUT /person/ryanne?friends&/person/sarah
PUT /person/ryanne?likes&/games/Fallout-3
... we automatically get:
GET /person/ryanne?relations --> ["friends", "likes"]