CODEWITHSUNDEEP
javadatabaseneo4j
Jessica
Jessica

Reputation: 235

Verify if the database is empty in neo4j

I'm working on neo4j in java and I have one question. When I create a node, how can I verify that the database is empty?

Here's my code to create a node:

br = new BufferedReader(new FileReader(csvFile));

        while (br.ready()==true) {
            transaction = graphDb.beginTx();
            int cont = 0;//limitador de tuplas por query
            while ((line = br.readLine()) != null && cont < 10000) {

                String[] dado = line.split(cvsSplitBy);

                // inserir comando para criar o nós com a data
                Node no = graphDb.createNode();
                no.setProperty("data", dado[0]);
                no.setProperty("temperatura", dado[1]);
                no.setProperty("latitude", dado[2]);
                no.setProperty("longitude", dado[3]);
                no.setProperty("variação", dado[4]);

                System.out.println(cont);
                cont++;
            }
            transaction.success();
            transaction.close();
        }

Upvotes: 2

Views: 1315

Answers (3)

cybersam
cybersam

Reputation: 67019

UPDATED ANSWER

Here is an efficient Cypher query that returns a boolean isEmpty result.

OPTIONAL MATCH (n)
RETURN n IS NULL AS isEmpty
LIMIT 1;

Upvotes: 2

Portable
Portable

Reputation: 323

match (n) 
return 1 
limit 1

I hope Neo4J would bother less processing this query, knowing it doesnt has to bother counting or bother filtering as suggested in previous answers

Upvotes: 1

FrobberOfBits
FrobberOfBits

Reputation: 18022

Execute a cypher query from java.

Use this query:

MATCH (n) RETURN count(n);

If the answer is zero, the database is empty. If it's anything else, it's not.

Upvotes: 4

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