Batch with unique relationships - neo4j

Question

Using Neo4J 2.0.0-M5, I'm trying to create my database using a batch, as is explained at :
http://docs.neo4j.org/chunked/milestone/rest-api-batch-ops.html
What I want to do is inserting nodes and relationships with the "get_or_create" mode, so that I can run the batch multiple times without creating redundant nodes and relationships.
Creating unique nodes can be done with /index/node/indexname?uniqueness=get_or_create, for example :
POST /db/data/batch [
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":0,"body":{"key":"nom", "value":"organisation", "properties": {"nom":"organisation"}}},
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":1,"body":{"key":"nom", "value":"établissement", "properties": {"nom":"établissement"}}}
]
However, I don't find how I can create a unique relationship between the two indexed nodes?
I want to state that there is a "est" relationship between "établissement" and "organisation". If I try with :
POST /db/data/batch [
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":0,"body":{"key":"nom", "value":"organisation", "properties": {"nom":"organisation"}}},
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":1,"body":{"key":"nom", "value":"établissement", "properties": {"nom":"établissement"}}},
{"method":"POST","to":"{1}/relationships","body":{"to":"{0}","type":"est"}},
{"method":"POST","to":"/index/relationship/my_rels?uniqueness=get_or_create","body":{"key":"nom","value":"est","uri":"{1}"}}
]
I get :
==> 500 Internal Server Error
==> {
==> "message" : "",
==> "exception" : "BatchOperationFailedException",
==> "fullname" : "org.neo4j.server.rest.domain.BatchOperationFailedException",
==> "stacktrace" : ["org.neo4j.server.rest.batch.NonStreamingBatchOperations.invoke(NonStreamingBatchOperations.java:63)", "org.neo4j.server.rest.batch.BatchOperations.performRequest(BatchOperations.java:188)", "org.neo4j.server.rest.batch.BatchOperations.parseAndPerform(BatchOperations.java:159)", "org.neo4j.server.rest.batch.NonStreamingBatchOperations.performBatchJobs(NonStreamingBatchOperations.java:48)", "org.neo4j.server.rest.web.BatchOperationService.batchProcess(BatchOperationService.java:123)", "org.neo4j.server.rest.web.BatchOperationService.performBatchOperations(BatchOperationService.java:73)", "java.lang.reflect.Method.invoke(Method.java:606)", "org.neo4j.server.rest.transactional.TransactionalRequestDispatcher.dispatch(TransactionalRequestDispatcher.java:132)", "org.neo4j.server.rest.security.SecurityFilter.doFilter(SecurityFilter.java:112)" ]
==> }
I'm stuck with this problem, so any advice would be really appreciated. Thank you!
Grégoire
EDIT: the problem seems to come from a bug that prevents unique nodes to be referenced from within a batch :
https://github.com/neo4j/neo4j/issues/84

Answer 1

The workaround (as stated in the github bug you mentioned) is to use Cypher.
Example using Batch and Cypher:
[
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":0,"body":{"key":"nom", "value":"organisation", "properties": {"nom":"organisation"}}},
{"method":"POST","to":"/index/node/concept?uniqueness=get_or_create","id":1,"body":{"key":"nom", "value":"établissement", "properties": {"nom":"établissement"}}},
{
"method": "POST",
"to": "/cypher",
"id": 1,
"body": {
"query" : "START a=node:concept(nom={aVal}), b=node:concept(nom={bVal}) CREATE b-[r:est]->a RETURN a, b, r",
"params" : {
"aVal" : "établissement",
"bVal" : "organisation"
}
}
}
]
Output:
[{
"id": 0,
"location": "http://localhost:7474/db/data/index/node/concept/nom/organisation/18688",
"body": {
"extensions": {},
"paged_traverse": "http://localhost:7474/db/data/node/18688/paged/traverse/{returnType}{?pageSize,leaseTime}",
"outgoing_relationships": "http://localhost:7474/db/data/node/18688/relationships/out",
"all_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/all/{-list|&|types}",
"traverse": "http://localhost:7474/db/data/node/18688/traverse/{returnType}",
"property": "http://localhost:7474/db/data/node/18688/properties/{key}",
"all_relationships": "http://localhost:7474/db/data/node/18688/relationships/all",
"self": "http://localhost:7474/db/data/node/18688",
"outgoing_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/out/{-list|&|types}",
"properties": "http://localhost:7474/db/data/node/18688/properties",
"incoming_relationships": "http://localhost:7474/db/data/node/18688/relationships/in",
"incoming_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/in/{-list|&|types}",
"create_relationship": "http://localhost:7474/db/data/node/18688/relationships",
"data": {
"nom": "organisation"
},
"indexed": "http://localhost:7474/db/data/index/node/concept/nom/organisation/18688"
},
"from": "/index/node/concept?uniqueness=get_or_create"
}, {
"id": 1,
"location": "http://localhost:7474/db/data/index/node/concept/nom/%EF%BF%BDtablissement/18689",
"body": {
"extensions": {},
"paged_traverse": "http://localhost:7474/db/data/node/18689/paged/traverse/{returnType}{?pageSize,leaseTime}",
"outgoing_relationships": "http://localhost:7474/db/data/node/18689/relationships/out",
"all_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/all/{-list|&|types}",
"traverse": "http://localhost:7474/db/data/node/18689/traverse/{returnType}",
"property": "http://localhost:7474/db/data/node/18689/properties/{key}",
"all_relationships": "http://localhost:7474/db/data/node/18689/relationships/all",
"self": "http://localhost:7474/db/data/node/18689",
"outgoing_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/out/{-list|&|types}",
"properties": "http://localhost:7474/db/data/node/18689/properties",
"incoming_relationships": "http://localhost:7474/db/data/node/18689/relationships/in",
"incoming_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/in/{-list|&|types}",
"create_relationship": "http://localhost:7474/db/data/node/18689/relationships",
"data": {
"nom": "�tablissement"
},
"indexed": "http://localhost:7474/db/data/index/node/concept/nom/%EF%BF%BDtablissement/18689"
},
"from": "/index/node/concept?uniqueness=get_or_create"
}, {
"id": 1,
"body": {
"columns": ["a", "b", "r"],
"data": [
[{
"paged_traverse": "http://localhost:7474/db/data/node/18689/paged/traverse/{returnType}{?pageSize,leaseTime}",
"outgoing_relationships": "http://localhost:7474/db/data/node/18689/relationships/out",
"data": {
"nom": "�tablissement"
},
"traverse": "http://localhost:7474/db/data/node/18689/traverse/{returnType}",
"all_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/all/{-list|&|types}",
"self": "http://localhost:7474/db/data/node/18689",
"all_relationships": "http://localhost:7474/db/data/node/18689/relationships/all",
"property": "http://localhost:7474/db/data/node/18689/properties/{key}",
"properties": "http://localhost:7474/db/data/node/18689/properties",
"outgoing_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/out/{-list|&|types}",
"incoming_relationships": "http://localhost:7474/db/data/node/18689/relationships/in",
"incoming_typed_relationships": "http://localhost:7474/db/data/node/18689/relationships/in/{-list|&|types}",
"extensions": {},
"create_relationship": "http://localhost:7474/db/data/node/18689/relationships"
}, {
"paged_traverse": "http://localhost:7474/db/data/node/18688/paged/traverse/{returnType}{?pageSize,leaseTime}",
"outgoing_relationships": "http://localhost:7474/db/data/node/18688/relationships/out",
"data": {
"nom": "organisation"
},
"traverse": "http://localhost:7474/db/data/node/18688/traverse/{returnType}",
"all_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/all/{-list|&|types}",
"self": "http://localhost:7474/db/data/node/18688",
"all_relationships": "http://localhost:7474/db/data/node/18688/relationships/all",
"property": "http://localhost:7474/db/data/node/18688/properties/{key}",
"properties": "http://localhost:7474/db/data/node/18688/properties",
"outgoing_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/out/{-list|&|types}",
"incoming_relationships": "http://localhost:7474/db/data/node/18688/relationships/in",
"incoming_typed_relationships": "http://localhost:7474/db/data/node/18688/relationships/in/{-list|&|types}",
"extensions": {},
"create_relationship": "http://localhost:7474/db/data/node/18688/relationships"
}, {
"start": "http://localhost:7474/db/data/node/18688",
"data": {},
"self": "http://localhost:7474/db/data/relationship/44187",
"property": "http://localhost:7474/db/data/relationship/44187/properties/{key}",
"properties": "http://localhost:7474/db/data/relationship/44187/properties",
"type": "est",
"extensions": {},
"end": "http://localhost:7474/db/data/node/18689"
}]
]
},
"from": "/cypher"
}]