Neo4j 3.5's embeded database does not seem to persist data

Question

I am trying to build a small command line tool that will store data in a neo4j graph. To do this I have started experimenting with Neo4j3.5's embedded databases. After putting together the following example I have found that either the nodes I am creating are not being saved to the database or the method of database creation is overwriting my previous run. The Example:

fun main() {
//Spin up data base
val graphDBFactory = GraphDatabaseFactory()
val graphDB = graphDBFactory.newEmbeddedDatabase(File("src/main/resources/neo4j"))
registerShutdownHook(graphDB)

val tx = graphDB.beginTx()

graphDB.createNode(Label.label("firstNode"))
graphDB.createNode(Label.label("secondNode"))

val result = graphDB.execute("MATCH (a) RETURN COUNT(a)")

println(result.resultAsString())
tx.success()
}

private fun registerShutdownHook(graphDb: GraphDatabaseService) {
// Registers a shutdown hook for the Neo4j instance so that it
// shuts down nicely when the VM exits (even if you "Ctrl-C" the
// running application).
Runtime.getRuntime().addShutdownHook(object : Thread() {
    override fun run() {
        graphDb.shutdown()
    }
})
}

I would expect that every time I run main the resulting query count will increase by 2. That is currently not the case and I can find nothing in the docs that references a different method of opening an already created embedded database. Am I trying to use the embedded database incorrectly or am I missing something? Any help or info would be appreciated.

build Info: Kotlin jvm 1.4.21 Neo4j-comunity-3.5.35

Answer 1

Transactions in neo4j 3.x have a 3 stage model

1. create
2. success / failure
3. close

you missed the third, which would then commit or rollback. You can use Kotlin's use as Transaction is an AutoCloseable