Neo4j check if node exists before creating?

I have a feeling I'm going about this all wrong. But anyway. I have an sql database which has essentially a purposefully denormalised table which I've constructed to make this task easier for me, so I can just grab stuff from one table. What I have is a table of pairs, something like this: ``` user_lo | user_hi | something_else | other stuff 1000 | 1234 | 1231251654 | 123 1050 | 1100 | 1564654 | 45648 1080 | 1234 | 456444894648 | 1 ``` And so on. So for my neo4j graph db, I want each user id as a node, the other stuff isn't too important but will be the stuff in the relations basically. I only want one node for each user, so my feeling is that if I do something like this: ``` while (rs.next()) { node_lo = db.createNode(); node_lo.setProperty("user_id", rs.getInt(1)); node_hi = db.createNode(); node_hi.setProperty("user_id", rs.getInt(2)); } ``` That when we add the node with user_id 1234 for the second time, it will just create a new node, but I what I want is for it to just grab this node instead of creating it so I can add it to the relationship to 1080 in this case. So what is the way to do this?