Neo4j merge's not saving data

Question

I have the following code using PHP & GraphAware:

$stack = $client->stack();
$stack->push('  MATCH (student:Student{id:123})
        MATCH (spring:Term{name:"Spring2017"})
        MATCH (class:Class{name:"Cypher101"})
        MERGE (student)-[:ENROLLED_IN]->(class)-[:FOR_TERM]->(spring)');
$results = $client->runStack($stack);

$res = $client->run('MATCH (n) RETURN count(n)');
print_r($res->records());

I have copied the example code found here: https://neo4j.com/developer/kb/understanding-how-merge-works/ and for some reason the print_r() returns the following:

Array
(
    [0] => GraphAware\Bolt\Record\RecordView Object
        (
            [keys:protected] => Array
                (
                    [0] => count(n)
                )

            [values:protected] => Array
                (
                    [0] => 0
                )

            [keyToIndexMap:GraphAware\Bolt\Record\RecordView:private] => Array
                (
                    [count(n)] => 0
                )

        )

)

If I run a CREATE command the query works fine but for some reason the code above won't. Can someone advise me what I'm doing wrong?

Your query seems correct. Can you check if the nodes you are matching exists in the database? — Rajendra Kadam, Jun 06 '19 at 11:59
Try this from Neo4j browser, if it works you may have missed something in your PHP code. — Rajendra Kadam, Jun 06 '19 at 12:00
They don't exist - because I though the merge would create them if not? — Antony, Jun 06 '19 at 12:00
Then you should replace `MATCH` with `MERGE` in the first 3 lines. — Rajendra Kadam, Jun 06 '19 at 12:02
Oh perfect!! Please make that an answer and I'll award it :o) — Antony, Jun 06 '19 at 12:06
Just one thing though - will that not overwrrite existing ones if there is a later duplicate? — Antony, Jun 06 '19 at 12:08
Nope, Merge will not overwrite. I recommend to create these nodes separately and keep your query as it is. — Rajendra Kadam, Jun 06 '19 at 12:10

score 2 · Accepted Answer · answered Jun 06 '19 at 12:09

Your query seems correct.

Check if these nodes exist in the Neo4j Database.

If these are not present in the database first create these nodes and then run the query.
You can also replace MATCH with MERGE, in that case, you don't
have to create these nodes separately.

NOTE: Multiple MERGE in a single query is not recommended, so try to use the first solution (creating the nodes separately).

Neo4j merge's not saving data

1 Answers1