CODEWITHSUNDEEP
neo4jneo4jclient
pradeep543
pradeep543

Reputation: 1

Create/Set RootNode in Neo4j graph db?

How do i set one of the node in the tree as a Root node ? Let say my index starts from 115, but when i am connecting to the db using Neo4jClient in dot net application am getting the root node as null ? Is it possible to set any node as root node ?

Upvotes: 0

Views: 487

Answers (2)

Tatham Oddie
Tatham Oddie

Reputation: 4290

This is not possible via the REST API, and thus not possible for Neo4jClient to support.

Upvotes: 0

Michal Bachman
Michal Bachman

Reputation: 2661

It's not possible using the standard API, but here's a little trick, assuming you can run some Java code. It allows you to create a new root node, I don't think there's a way to change node IDs.

public class RootNodeCreator {

    /**
     * Create the root node. Make sure the database is stopped when running this.
     *
     * @param pathToDatabase path to the database.
     */
    public void createRoot(String pathToDatabase) {
        BatchInserter inserter = BatchInserters.inserter(pathToDatabase);
        inserter.createNode(0, new HashMap<String, Object>());
        inserter.shutdown();
    }
}

and a test:

@Test
public void verifyRootCreation() throws IOException {
    TemporaryFolder temporaryFolder = new TemporaryFolder();
    temporaryFolder.create();

    GraphDatabaseService database = new GraphDatabaseFactory().newEmbeddedDatabase(temporaryFolder.getRoot().getAbsolutePath());
    Transaction tx = database.beginTx();
    try {
        database.getNodeById(0).delete();
        tx.success();
    }
    finally {
        tx.finish();
    }


    try {
        database.getNodeById(0);
        fail();
    } catch (NotFoundException e) {
        //ok
    }

    database.shutdown();

    new RootNodeCreator().createRoot(temporaryFolder.getRoot().getAbsolutePath());

    database = new GraphDatabaseFactory().newEmbeddedDatabase(temporaryFolder.getRoot().getAbsolutePath());
    assertNotNull(database.getNodeById(0));
}

Upvotes: 1

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