Apoc.do.WHEN How to handle parameters

Neo4j Graph Platform
1

Hello friends,

i want to execute the following query, but i dont know how to handle the parameters. As you can see, i need to know leaf,ws and r inside the apoc.when. How am I supposed to set the parameters?

MATCH (ws:Workspace{wsId:1})-[r:OP]->(leaf:Event) WITH leaf,ws, r
CALL apoc.do.when(leaf IS NULL,"CREATE (ws)-[:OP]->(e:Event{elementId:1, name:'TestElem1'})","DELETE r WITH ws,leaf CREATE (ws)-[:OP]->(e:Event{elementId:1, name:'TestElem1'})-[:OP]->(leaf)",{}) YIELD value

Currently, i get this error:

a
a830Ă—199 17.7 KB

Thank you in advance

2

The error is because your query concludes with a “call” that has a “yield” without a “return”. Add a “return”

You pass parameters to the apoc.do.when method with a map of your parameters.

Try this:

MATCH (ws:Workspace{wsId:1})-[r:OP]->(leaf:Event) 
WITH leaf,ws, r
CALL apoc.do.when(
  leaf IS NULL,
  "CREATE (ws)-[:OP]->(e:Event{elementId:1, name:'TestElem1'})",
  "DELETE r WITH ws,leaf CREATE (ws)-[:OP]->(e:Event{elementId:1, name:'TestElem1'})-[:OP]->(leaf)",
  {ws:ws, leaf:leaf, r:r}
) YIELD value
Return 1
1 Like
3

Hey Gary
Thank you very much. It worked :ok_hand: :clap: :+1:

1 Like