Should I normalize my Neo4j object graph?

I have started playing around with db4o but quite soon I have run into a problem of when I remove a link then I have to remove a link somewhere else. Can I enforce constraints, as I can with a relational data开发者_开发技巧base?

Neo4j guarantees that relationships are at all times connected to exactly two nodes: a start node and an end node. In Neo4j relationships are first class citizens, and you don't need to bother about how they are implemented.