Neo4j Bolt Driver for Julia

Neo4jBolt.jl is a Julia port of the official Neo4j Driver (1.7). It supports Neo4j 3.0 and above using the fast binary Bolt protocal. The Bolt driver is designed to be much faster than the HTTP REST based driver.

Todo

Encrypted SSL connections and cluster routing have not yet been implemented in this version.

Getting Started with Neo4j

Quick Examples

Here are a few usage examples. For a more extensive collection of examples see the integration tests in the test/integration directory of this repository.

Run Cypher Statement

using Neo4jBolt  

driver = Neo4jBoltDriver("bolt://localhost:7687", auth=("neo4j", "password"))

session(driver) do sess
    result = run(sess, "UNWIND(RANGE(1, 10)) AS z RETURN z")
    for record in result
        println(record["z"])
    end
end

Run Simple Transaction

using Neo4jBolt  

driver = Neo4jBoltDriver("bolt://localhost:7687", auth=("neo4j", "password"))

session(driver) do sess
    begin_transaction(sess) do tx
        result = run(tx, "CREATE (a:Person {name:'Alice'}) RETURN a")
        v = value(single(result))
        println(v.labels == Set(["Person"]))
        println(v.properties == Dict("name"=>"Alice"))
    end
end

Unit of Work transactions

using Neo4jBolt  

driver = Neo4jBoltDriver("bolt://localhost:7687", auth=("neo4j", "password"))

function add_friend(tx, args, kwargs)
    run(tx, "MERGE (a:Person {name: \$name}) " *
            "MERGE (a)-[:KNOWS]->(friend:Person {name: \$friend_name})", name=args[1], friend_name=args[2])
end

function print_friends(tx, args, kwargs)
    for record in run(tx, "MATCH (a:Person)-[:KNOWS]->(friend) WHERE a.name = \$name " *
                          "RETURN friend.name ORDER BY friend.name", name=args[1])
        println(record["friend.name"])
    end
end        

session(driver) do sess
    write_transaction(sess, add_friend, "Arthur", "Guinevere")
    write_transaction(sess, add_friend, "Arthur", "Lancelot")
    write_transaction(sess, add_friend, "Arthur", "Merlin")
    read_transaction(sess, print_friends, "Arthur")
end

Implementation Details

Dates and Times

By default Neo4j Date, Time and Duration types are returned as Julia Date, Time, DateTime, ZonedDateTime or Dates.CompoundPeriod types where appropriate. However, Julia Dates and Neo4j Dates are slightly incompatible. Specifically, Julia DateTimes do not support nanosecond time. Julia Times do not support TimeZones. Also Julia's TimeZone system is not entirely compatible with Neo4j's. As a workaround to these incompatibilities, you can choose to use the provided DateWrapper, TimeWrapper, DateTimeWrapper and DurationWrapper types instead. These wrap Neo4j's native representations in Julia struct types. To return these wrapper types from a query set use_julia_dates=false as a keyword argument to the run method.

# Here a ZonedDateTime is returned but the nanosecods are truncated

session(tc.driver) do sess
      result = run(sess,"RETURN datetime('1976-06-13T12:34:56.789012345[Europe/London]')")
      v = value(single(result))
      @test isa(v, ZonedDateTime)
      @test v == ZonedDateTime(DateTime(1976, 6, 13, 12, 34, 56, 789), tz"Europe/London")
end

# Here a DateTimeWrapper is returned and nanosecods are not truncated

session(tc.driver) do sess
      result = run(sess, "RETURN datetime('1976-06-13T12:34:56.789012345[Europe/London]')", use_julia_dates=false)
      v = value(single(result))
      @test isa(v, DateTimeWrapper)
      @test v == DateTimeWrapper(1976, 6, 13, 12, 34, 56, 789012345, timezone="Europe/London")
end

virtualgraham / Neo4jBolt.jl

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