MERGE cypher not returning a value?

[Kevin Burton]

Enter code here...

I have a cypher query that looks like:

return new Promise(function (resolve, reject) {

        db.cypher({
                query: 'MATCH (fi:FormDefinitionImageIndex {id: ' + row.formDefinitionImageIndexFieldID + '}),' +
                '(d:FormDefinitionImage {id: ' + row.formDefinitionImageID + '})' +
                ' MERGE (fi)-[:IMAGEINDEX]->(d) '
            },
            function (err, result) {
                if (err) {
                    return reject(err);
                } else {
                    return resolve(result);
                }
            });
    }).then(function (results) {
        if(results.length == 0) {
            console.log('No FormDefinitionImageIndexField relationships for (' + row.formDefinitionImageIndexFieldID + ' <-> ' + row.formDefinitionImageID + ') index field key ' + row.indexFieldKey);
        } else {
            console.log('FormDefinitionImageIndexField relationship ' + results.length);
        }
        return results;
    });

As can be seen from the code I would expect an array of results when the promise is "resolved". But instead I am getting a single zero lengthed array. The cypher query forms the relationship but it is odd that the return value is empty. Ideas?

Thank you.

Kevin

[Michael Hunger]

1. you should use parameters, not string concatenation

2. if either of the matches doesn't match anything the merge will never be called, make sure they actually both produce a hit

[Kevin Burton]

Thank you for your recommendation to use parameters. The query is succeeding because I can go on the browser interface and see the relationship created. It doesn't seem to pass a pass/fail indication.

[Michael Hunger]

Oh sorry and you don't return anything, so it will return nothing as you requested :).

[Kevin Burton]

I am going to take your suggestion. But I am having a problem with the understanding.of how properties are used. Say I have the following query:

db.cypher({ query: 'MATCH (r:AutoFillRule {id: ' + row.autoFillRuleID + '}), ' +
                   '(g:AutoFillRuleGroup {id: ' + row.autoFillRuleGroupID + '})' +
                   ' MERGE (r)-[:AUTOFILL]->(g)' +
                   ' RETURN COUNT(*)'

Notice that the property key is the same for both places that I would like to use properties. So I cannot just do something like: 'props['id'] = row.autoFillRuleGroupID' How should I use properties in this case? Thanks again.

On Thursday, January 28, 2016 at 3:19:25 PM UTC-6, Michael Hunger wrote:

[Michael Hunger]

I said parameters not properties :)

db.cypher({ query: 'MATCH (r:AutoFillRule {id: {autoFillRuleId}}), ' +
                   '(g:AutoFillRuleGroup {id: {autoFillRuleGroupID}})' +

                   ' MERGE (r)-[:AUTOFILL]->(g)' +

                   ' RETURN COUNT(*)', params: {autoFillRuleId: row.autoFillRuleID, autoFillRuleGroupID, row.autoFillRuleGroupID  })