问题
I've started to use Neo4j-ogm inside my application and it works like charm for fixed object domain model. When I know which node type connected to another node with known type - it can be easily mapped. However, in my opinion versitality of Neo4j graph database is also in an ability to work with un-typed (or dynamic) domain models and I'm having conceptual problem to understand how to achieve it with Neo4j-ogm.
Let me describe my problem with an example.
I have domain objects like: Message and Feature. Where Message can have multiple features and a Feature can be a part of many messages. It is completely ok to map with Neo4j-ogm.
Then what if user want to relate the message to some Task node type or refer it to some Contact node type ? In my application it is possible to have large (but limited) set of connection between nodes of various types. So I would like to be able to get all types of connections from a particular node, regardless of this connection types or endNode types?
Of course I can use cypher to create connections like this:
MATCH ($2911) WHERE id($2911)={$2911} MATCH ($2912) WHERE id($2912)={$2912} MERGE ($2911)-[_0:`part_of` {$aid} ]->($2912) RETURN id(_0) AS _0
but when I'm starting doing this - I would need a way how to convert results of this queries to and from relational entities myself.
Is there a gracefull way to do this using Neo4j-ogm. May be it is possible to create a comprehansive type heirarchy or something which will allow to use Neo4j-ogm together for fixed and dynamic domain object models.
Thank you in advance.
回答1:
A fixed type hierarchy is supported by Neo4j OGM so if you are able to represent your domain in such a hierarchy, you should be able to fetch all connections from a single entity. This means that the end nodes must be also represented in this hierarchy.
Run time polymorphism is not supported in the current version- it's up for discussion though, so depending on how it goes, it might make it to a future release.
来源：https://stackoverflow.com/questions/33956078/neo4j-ogm-for-dynamic-domain-object-model