RNeo4j Error: 400 Bad Request - neo4j

Question

I am not sure why I am getting the error below, but I suppose it's something that I am doing wrong.
First, you can grab my dataset by downloading the file dataset.r from this link and loading it into your session with dget("dataset.r").
In my case, I would do dat = dget("dataset.r").
The code below is what I am using to load data into the Neo4j.
library(RNeo4j)
graph = startGraph("http://localhost:7474/db/data/")
graph$version
# sure that the graph is clean -- you should backup first!!!
clear(graph, input = FALSE)
## ensure the constraints
addConstraint(graph, "School", "unitid")
addConstraint(graph, "Topic", "topic_id")
## create the query
## BE CAREFUL OF WHITESPACE between KEY:VALUE pairs for parameters!!!
query = "
MERGE (s:School {unitid:{unitid},
instnm:{instnm},
obereg:{obereg},
carnegie:{carnegie},
applefeeu:{applfeeu},
enrlft:{enrlft},
applcn:{applcn},
admssn:{admssn},
admit_rate:{admit_rate},
ape:{ape},
sat25:{sat25},
sat75:{sat75} })
MERGE (t:Topic {topic_id:{topic_id},
topic:{topic} })
MERGE (s)-[:HAS_TOPIC {score:{score} }]->(t)
"
for (i in 1:nrow(dat)) {
## status
cat("starting row ", i, "\n")
## run the query
cypher(graph,
query,
unitid = dat$unitid[i],
instnm = dat$instnm[i],
obereg = dat$obereg[i],
carnegie = dat$carnegie[i],
applfeeu = dat$applfeeu[i],
enrlft = dat$enrlt[i],
applcn = dat$applcn[i],
admssn = dat$admssn[i],
admit_rate = dat$admit_rate[i],
ape = dat$apps_per_enroll[i],
sat25 = dat$sat25[i],
sat75 = dat$sat75[i],
topic_id = dat$topic_id[i],
topic = dat$topic[i],
score = dat$score[i] )
} #endfor
I can successfully load the first 49 records of my dataframe dat, but errors out on the 50th row.
This is the error that I recieve:
starting row 50
Show Traceback
Rerun with Debug
Error: 400 Bad Request
{"message":"Node 1477 already exists with label School and property \"unitid\"=[110680]","exception":"CypherExecutionException","fullname":"org.neo4j.cypher.CypherExecutionException","stacktrace":["org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_1$spi$ExceptionTranslatingQueryContext$$translateException(ExceptionTranslatingQueryContext.scala:154)","org.neo4j.cypher.internal.compiler.v2_1.spi.ExceptionTranslatingQueryContext$ExceptionTranslatingOperations.setProperty(ExceptionTranslatingQueryContext.scala:121)","org.neo4j.cypher.internal.compiler.v2_1.spi.UpdateCountingQueryContext$CountingOps.setProperty(UpdateCountingQueryContext.scala:130)","org.neo4j.cypher.internal.compiler.v2_1.mutation.PropertySetAction.exec(PropertySetAction.scala:51)","org.neo4j.cypher.internal.compiler.v2_1.mutation.MergeNodeAction$$anonfun$exec$1.apply(MergeNodeAction.scala:80)","org.neo4j.cypher.internal.compiler.v2_1
Here is my session info:
> sessionInfo()
R version 3.1.0 (2014-04-10)
Platform: x86_64-apple-darwin13.1.0 (64-bit)
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] RNeo4j_1.2.0
loaded via a namespace (and not attached):
[1] RCurl_1.95-4.1 RJSONIO_1.2-0.2 tools_3.1.0
And it's worth noting that I am using Neo4j 2.1.3.
Thanks for any help in advance.

Answer 1

This is an issue with how MERGE works. By setting the score property within the MERGE clause itself here...
MERGE (s)-[:HAS_TOPIC {score:{score} }]->(t)
...MERGE tries to create the entire pattern, and thus your uniqueness constraint is violated. Instead, do this:
MERGE (s)-[r:HAS_TOPIC]->(t)
SET r.score = {score}
I was able to import all of your data after making this change.