Java与Neo4j Cypher

Question

I want to create a relationship between a certain node (user) to all other nodes (items) with id in a list parameter :
i wrote this query :

"FOREACH(it in {h_items} | "
" MATCH (u:User),(i:Item)"
" WHERE u.username = "+username+" AND i.itemId = it"
" CREATE (u)-[h:HAVE_HOBBY]->(i)"
" RETURN r

which should create a relationshipt between user with "username" to item that have itemId = it.
it should be iterator on a list of items that i give to :

ArrayList<String> hobby_items = new ArrayList<String>();
HashMap<String, Object> params = new HashMap<String, Object>();
params.put("h_items", hobby_items);
execute(query,param);  

this gives the error :

Invalid use of MATCH inside FOREACH

as it turned out that match inside foreach isn't allowed .
what is the write way to write this query ?

Answer 1

This may work for you:

MATCH (u:User)
WHERE u.username = { username }
UNWIND { h_items } AS it
MATCH (i:Item)
WHERE i.itemId = it
CREATE (u)-[:HAVE_HOBBY]->(i)
RETURN u, i;

You would provide {username} and {h_items} as parameters. Your query returned r , which is not defined, so this query returns u and i .