spring data neo4j 3.0.0 - why two labels set by default

Question

I need to write batch importing utility for my Neo4j database but I don't want to lose the repository feature of SDN. To achieve this goal I want to insert such nodes that can be still queried using auto generated repository methods.

I inserted some nodes to my database and I looked at their properties and labels to see how they are set and I noticed that SDN inserted nodes have two labels. For example nodes representing class SomeClass have labels: ["_SomeClass", "SomeClass"]. My question is: why set two, almost identical labels for each node?

Answer 1

Oh that's actually simple. We somehow have to note if the current node is of type SomeClass, which we do by prepending the "_". As there are labels added for each super-type you need to differentiate what the actual type of the node in Spring Data Neo4j is.

So you could have: _Developer, Developer, Employee, Person for a class hierarchy from Person down to Developer. And then there could be additional labels for interfaces.

When you now do: DeveloperRepository.findAll() then you only want those with _Developer back, not ones that derived from Developer.