Ways to remember and reuse previous query result in Neo4j

Question

I am coding in Ruby using Neo4j with the gem Neography. When doing query, I use the method execute_neo4j_query provided by Neography. I am not sure about the best practice.

Suppose I use following code to fetch a user:

user1 = @neo.execute_neo4j_query("
      MATCH (user:User {user_id: '#{params[:user_id_1]}'})
      RETURN id(user)
      LIMIT 1
      ")

and to fetch another user similarly

user2 = @neo.execute_neo4j_query("
      MATCH (user:User {user_id: '#{params[:user_id_2]}'})
      RETURN id(user)
      LIMIT 1
      ")

Then I did some stuff with this two users.

Now I need to create an edge between this two users, so I did this

@neo.execute_neo4j_query("
      MATCH (user1:User {user_id: '#{params[:user_id_2]}'})
      MATCH (user2:User {user_id: '#{params[:user_id_2]}'})
      CREATE UNIQUE (user1)-[:FOLLOW]->(user2)
      ")

However, I believe such approach is not optimal, since I queried for the same two users twice.

My question is:

1) Is there a way to reuse previously queried results using Neography?

2) Is it recommended to use methods provided by Neography such as @neo.create_node other than using execute_neo4j_query directly? I choose the latter because I am not sure if the encapsulated methods can satisfy my task. So, if you can rewrite my above codes in native Neography code, it will be greatly appreciated.

Answer 1

1. Don't use start anymore if you don't know why you would use it
2. use the transactional cypher support in neography
3. Use Parameters in your cypher queries, like MATCH (u:User {name:{name}}) RETURN u

Answer 2

I don't know Neography, but I can take a shot at answering question #1, since that appears to be answerable by changing your third Cypher query.

Since your 2 initial queries seem to be getting the node IDs for user 1 and user 2, you should be able to avoid searching again for those nodes by using the START clause. You will need to specify a parameter map with the 2 node IDs returned by the first 2 queries.

  START user1=node(#{params[:node_id_1]}), user2=node(#{params[:node_id_2]})
  CREATE UNIQUE (user1)-[:FOLLOW]->(user2)

Answer 3

I do not know Neography either, but you can simplify the query slightly, with this one liner:

   MATCH (a:User),(b:User) WHERE a.userId ={id1} AND b.userId = {id2} CREATE UNIQUE (a)-[r:FOLLOWS]->(b) RETURN r