如何在一个事务中的不同节点之间添加多个关系

Question

I have created many nodes in Neo using Neo4jClient in one go, i mean in single transaction. Now want to create different relationships in between them. I know left nodes, right nodes and relationship in between them. But its a list not single relationship.

I don't find any way to create multiple relationships between multiple existing nodes in single transaction.

I am struck at this very badly. If there is any solution for this please help me.

Answer 1

Assume we have 3 nodes defined as: CREATE (a:A), (b:B), (c:C)

Then depending on how many relationships you're trying to create at once and how they're organised, I can suggest two possible options:

1. If you can list your relationships out into a single unbroken merge expression (the merge syntax doesn't currently allow more than one pattern), you can easily create multiple relationships like this:

   MATCH (a:A), (b:B), (c:C) MERGE (a)-[:REL1]->(b)-[:REL2]->(c)-[:REL3]->(a)

2. Otherwise, if the structure is too complex to write out in that way, you can use:

   MATCH (a:A), (b:B), (c:C) MERGE (a)-[:REL1]->(b) MERGE (b)-[:REL2]->(c) MERGE (c)-[:REL3]->(a)

Finally, I guess it's worth pointing out the obvious, that if you're using the transactional endpoint of the server, then even breaking these into separate statements would still operate atomically, although of course you'd probably be incurring the penalty of multiple MATCH clauses, so the performance may be worse.