Document

Annotation @Document

The annotations @Document applied to a class marks this class as a candidate for mapping to the database. The most relevant parameter is value to specify the collection name in the database. The annotation @Document specifies the collection type to DOCUMENT.

@Document(value="persons")
public class Person {
  ...
}

Spring Expression support

Spring Data ArangoDB supports the use of SpEL expressions within @Document#value. This feature lets you define a dynamic collection name which can be used to implement multi tenancy applications.

@Component
public class TenantProvider {

  public String getId() {
    // threadlocal lookup
  }

}

@Document("#{tenantProvider.getId()}_persons")
public class Person {
  ...
}

Annotation @From and @To

With the annotations @From and @To applied on a collection or array field in a class annotated with @Document the nested edge objects are fetched from the database. Each of the nested edge objects has to be stored as separate edge document in the edge collection described in the @Edge annotation of the nested object class with the _id of the parent document as field _from or _to.

@Document("persons")
public class Person {
  @From
  private List<Relation> relations;
}

@Edge(name="relations")
public class Relation {
  ...
}

The database representation of Person in collection persons looks as follow:

{
  "_key" : "123",
  "_id" : "persons/123"
}

and the representation of Relation in collection relations:

{
  "_key" : "456",
  "_id" : "relations/456",
  "_from" : "persons/123"
  "_to" : ".../..."
}
{
  "_key" : "789",
  "_id" : "relations/456",
  "_from" : "persons/123"
  "_to" : ".../..."
}
...

Note: The annotations @From and @To also work on non-collection/non-array fields. If multiple edges are linked with the entity, it is not guaranteed that the same edge is returned every time. Use at your own risk.