Cypher supports queries with parameters which are submitted as a JSON map.

START x  = node:node_auto_index(name={startName})
MATCH path = (x-[r]-friend)
WHERE friend.name = {name}
RETURN TYPE(r)

Figure 22.3. Final Graph

Example request

{
  "query" : "start x  = node:node_auto_index(name={startName}) match path = (x-[r]-friend) where friend.name = {name} return TYPE(r)",
  "params" : {
    "startName" : "I",
    "name" : "you"
  }
}

Example response

{
  "columns" : [ "TYPE(r)" ],
  "data" : [ [ "know" ] ]
}

A simple query returning all nodes connected to node 1, returning the node and the name property, if it exists, otherwise null:

START x  = node(340)
MATCH x -[r]-> n
RETURN type(r), n.name?, n.age?

Figure 22.4. Final Graph

Example request

{
  "query" : "start x  = node(340) match x -[r]-> n return type(r), n.name?, n.age?",
  "params" : {
  }
}

Example response

{
  "columns" : [ "type(r)", "n.name?", "n.age?" ],
  "data" : [ [ "know", "him", 25 ], [ "know", "you", null ] ]
}

Paths can be returned together with other return types by just specifying returns.

START x  = node(344)
MATCH path = (x--friend)
RETURN path, friend.name

Figure 22.5. Final Graph

Example request

{
  "query" : "start x  = node(344) match path = (x--friend) return path, friend.name",
  "params" : {
  }
}

Example response

{
  "columns" : [ "path", "friend.name" ],
  "data" : [ [ {
    "start" : "http://localhost:7474/db/data/node/344",
    "nodes" : [ "http://localhost:7474/db/data/node/344", "http://localhost:7474/db/data/node/343" ],
    "length" : 1,
    "relationships" : [ "http://localhost:7474/db/data/relationship/198" ],
    "end" : "http://localhost:7474/db/data/node/343"
  }, "you" ] ]
}

When sending queries that return nested results like list and maps, these will get serialized into nested JSON representations according to their types.

START n = node(342,341)
RETURN collect(n.name)

Figure 22.6. Final Graph

Example request

{
  "query" : "start n = node(342,341) return collect(n.name)",
  "params" : {
  }
}

Example response

{
  "columns" : [ "collect(n.name)" ],
  "data" : [ [ [ "I", "you" ] ] ]
}

By passing in an extra parameter, you can ask the cypher executor to return a profile of the query as it is executed. This can help in locating bottlenecks.

START x  = node(335)
MATCH x -[r]-> n
RETURN type(r), n.name?, n.age?

Figure 22.7. Final Graph

Example request

{
  "query" : "start x  = node(335) match x -[r]-> n return type(r), n.name?, n.age?",
  "params" : {
  }
}

Example response

{
  "columns" : [ "type(r)", "n.name?", "n.age?" ],
  "data" : [ [ "know", "him", 25 ], [ "know", "you", null ] ],
  "plan" : {
    "args" : {
      "returnItemNames" : [ "type(r)", "n.name?", "n.age?" ],
      "_rows" : 2,
      "_db_hits" : 0,
      "symKeys" : [ "x", "n", "n.name?", "n.age?", "type(r)", "r" ]
    },
    "dbHits" : 0,
    "name" : "ColumnFilter",
    "children" : [ {
      "args" : {
        "_rows" : 2,
        "_db_hits" : 4,
        "exprKeys" : [ "type(r)", "n.name?", "n.age?" ],
        "symKeys" : [ "n", "x", "r" ]
      },
      "dbHits" : 4,
      "name" : "Extract",
      "children" : [ {
        "args" : {
          "trail" : "(x)-[r WHERE true AND true]->(n)",
          "_rows" : 2,
          "_db_hits" : 3
        },
        "dbHits" : 3,
        "name" : "TraversalMatcher",
        "children" : [ {
          "args" : {
            "_rows" : 1,
            "_db_hits" : 0
          },
          "dbHits" : 0,
          "name" : "ParameterPipe",
          "children" : [ ],
          "rows" : 1
        } ],
        "rows" : 2
      } ],
      "rows" : 2
    } ],
    "rows" : 2
  }
}

Errors on the server will be reported as a JSON-formatted stacktrace and message.

START x = node(325)
RETURN x.dummy

Figure 22.8. Final Graph

Example request

{
  "query" : "start x = node(325) return x.dummy",
  "params" : {
  }
}

Example response

{
  "message": "The property \u0027dummy\u0027 does not exist on Node[325]",
  "exception": "EntityNotFoundException",
  "fullname": "org.neo4j.cypher.EntityNotFoundException",
  "stacktrace": [
    "org.neo4j.cypher.internal.helpers.MapSupport$PropertyContainerMap$$anonfun$apply$1.apply(MapSupport.scala:64)",
    "org.neo4j.cypher.internal.helpers.MapSupport$PropertyContainerMap$$anonfun$apply$1.apply(MapSupport.scala:64)",
    "scala.Option.getOrElse(Option.scala:120)",
    "org.neo4j.cypher.internal.helpers.MapSupport$PropertyContainerMap.apply(MapSupport.scala:64)",
    "org.neo4j.cypher.internal.helpers.MapSupport$PropertyContainerMap.apply(MapSupport.scala:52)",
    "org.neo4j.cypher.internal.commands.expressions.Property.apply(Property.scala:31)",
    "org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$internalCreateResults$1$$anonfun$apply$1.apply(ExtractPipe.scala:47)",
    "org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$internalCreateResults$1$$anonfun$apply$1.apply(ExtractPipe.scala:45)",
    "scala.collection.immutable.Map$Map1.foreach(Map.scala:109)",
    "org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$internalCreateResults$1.apply(ExtractPipe.scala:45)",
    "org.neo4j.cypher.internal.pipes.ExtractPipe$$anonfun$internalCreateResults$1.apply(ExtractPipe.scala:44)",
    "scala.collection.Iterator$$anon$11.next(Iterator.scala:328)",
    "scala.collection.Iterator$$anon$11.next(Iterator.scala:328)",
    "org.neo4j.cypher.internal.ClosingIterator$$anonfun$next$1.apply(ClosingIterator.scala:44)",
    "org.neo4j.cypher.internal.ClosingIterator.failIfThrows(ClosingIterator.scala:86)",
    "org.neo4j.cypher.internal.ClosingIterator.next(ClosingIterator.scala:43)",
    "org.neo4j.cypher.PipeExecutionResult.next(PipeExecutionResult.scala:135)",
    "org.neo4j.cypher.PipeExecutionResult.next(PipeExecutionResult.scala:32)",
    "scala.collection.Iterator$$anon$11.next(Iterator.scala:328)",
    "scala.collection.convert.Wrappers$IteratorWrapper.next(Wrappers.scala:30)",
    "org.neo4j.helpers.collection.ExceptionHandlingIterable$1.next(ExceptionHandlingIterable.java:67)",
    "org.neo4j.helpers.collection.IteratorWrapper.next(IteratorWrapper.java:47)",
    "org.neo4j.server.rest.repr.ListRepresentation.serialize(ListRepresentation.java:58)",
    "org.neo4j.server.rest.repr.Serializer.serialize(Serializer.java:75)",
    "org.neo4j.server.rest.repr.MappingSerializer.putList(MappingSerializer.java:61)",
    "org.neo4j.server.rest.repr.CypherResultRepresentation.serialize(CypherResultRepresentation.java:57)",
    "org.neo4j.server.rest.repr.MappingRepresentation.serialize(MappingRepresentation.java:42)",
    "org.neo4j.server.rest.repr.OutputFormat.assemble(OutputFormat.java:179)",
    "org.neo4j.server.rest.repr.OutputFormat.formatRepresentation(OutputFormat.java:131)",
    "org.neo4j.server.rest.repr.OutputFormat.response(OutputFormat.java:117)",
    "org.neo4j.server.rest.repr.OutputFormat.ok(OutputFormat.java:55)",
    "org.neo4j.server.rest.web.CypherService.cypher(CypherService.java:95)",
    "java.lang.reflect.Method.invoke(Method.java:597)"
  ]
}