CODEWITHSUNDEEP
neo4j
sabbir
sabbir

Reputation: 2025

MERGE/CREATE in neo4j UNWIND

I have following data (Info) in Neo4j Label:

{
   domain:"domain1.com",
   email: "[email protected]"
},
{
   domain:"domain2.com",
   email: "[email protected]"
}
..................
..................

Now I want to insert data into Info if new domain is found, otherwise merge.

I've tried the following CQL:

 WITH [{domain:"domain1.com", email: "[email protected]"}, 
       {domain:"domain3.com", email: "[email protected]"}] as arr

   UNWIND arr as ar
      MATCH (x:Info) WHERE x.domain = ar.domain
      WITH count(x) as c, ar
      CALL apoc.do.when( c <> 0, 
         'MERGE (a:Info {domain: ar.domain}) ON SET a.email=ar.email return a', 
         'CREATE (a:Info { domain: ar.domain, email: ar.email }) return a',
         { c:c, ar:arr }) YEILD value
       RETURN value

In above CQL, only merge is working, but nothing created.

Any suggestion?

Thanks in advance.

Upvotes: 0

Views: 1107

Answers (1)

InverseFalcon
InverseFalcon

Reputation: 30407

You're mixing up ar and arr all over the place here.

In your outer query arr is a list. Yet you pass arr in for ar in your apoc.do.when() call and treat it as a map (ar.domain and ar.email obviously won't work here within apoc.do.when())

You're also referencing arr.domain and arr.email in the else part of apoc.do.when(), but arr isn't in scope.

You also don't need to pass c into the procedure call; the evaluation in the first argument uses the existing scope, only the queries after that require you to pass variables between scope.

Also ON SET isn't valid, you have to use ON MATCH SET, ON CREATE SET, or just SET.

All this said, you don't even need to use apoc.do.when(), it looks like you only need to use MERGE and SET:

WITH [{domain:"domain1.com", email: "[email protected]"}, 
       {domain:"domain3.com", email: "[email protected]"}] as arr

UNWIND arr as ar
MERGE (x:Info {domain:ar.domain}) 
SET x.email = ar.email
RETURN x

Remember that MERGE is like a MATCH or CREATE (when no matches are found), so after the MERGE it will always be bound to a node, either an existing node or a newly created node, and since you want to set the email property in either case, we can just use SET here.

Upvotes: 1

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