Prerequisites:
- a working Docker Neo4j container
- you are working with 3.3.1 version of the Neo4j Community Edition (CE)
Your options
By default, Neo4j CE comes with graph.db database that is awaiting to be populated with nodes, labels, properties and relationships. You will find this database at ~/neo4j/data/databases/graph.db/. If you have not created any nodes or imported any data then graph.db remains empty or clean.
If that is the case then you don’t need to read the rest of this post.
However, if you have already done some work insidegraph.db then you will need to make some changes to the database before importing any CSV data.
Already played with Neo4j?
If you have already run some queries then you will notice that your Neo4j Browser’s Database Information tab will display something like this:
Therefore, before you can import fresh data, you will need to clear out all nodes, labels, properties and relationships. On the surface this would appear to be very simple; and it should be but it’s not.
You can go to your Neo4j Browser and run the following command:
MATCH (n) DETACH DELETE n;
The command above is designed to remove all nodes and all the information related to it. However, that is not what happens in reality.
Yes, the system does say the following:
Deleted 3320 nodes, deleted 12675 relationships, completed after 174 ms.
The Gotcha
But Neo4j Browser’s Database Information tab displays something unexpected:
You can also use these Cypher statements to confirm the above:
CALL db.labels();
CALL db.propertyKeys();
And the database size has increased!
The workaround
So here’s what we will do:
- Go to the terminal where you started Neo4j service inside the Docker container, and using Ctrl+C stop that service
... 2018-01-11 09:33:09.218+0000 INFO Neo4j Server shutdown initiated by request 2018-01-11 09:33:09.231+0000 INFO Stopping... 2018-01-11 09:33:09.492+0000 INFO Stopped. - Remove files under
~/neo4j/data/databases/graph.db/directory that refer to the above labels and property keys inside thegraph.dbdatabasesudo rm -rf neo4j/data/databases/graph.db/*.* - Restart the Neo4j Docker container and the response you can expect to see is:
Active database: graph.db Directories in use: home: /var/lib/neo4j config: /var/lib/neo4j/conf logs: /logs plugins: /var/lib/neo4j/plugins import: /var/lib/neo4j/import data: /var/lib/neo4j/data certificates: /var/lib/neo4j/certificates run: /var/lib/neo4j/run Starting Neo4j. 2018-01-11 09:39:11.347+0000 INFO ======== Neo4j 3.3.1 ======== 2018-01-11 09:39:11.369+0000 INFO Starting... 2018-01-11 09:39:12.302+0000 INFO Bolt enabled on 0.0.0.0:7687. 2018-01-11 09:39:15.252+0000 INFO Started. 2018-01-11 09:39:16.093+0000 INFO Remote interface available at http://localhost:7474/ - Go back to Neo4j Browser and have a look at the Database Information tab:
N.B.:
We can also wrap all of the above commands inside a shell script adapted from StackOverflow[1]
#!/bin/sh
# script for clearing local graph.db database linked to Docker Neo4j container
echo Deleting all nodes and relationships from running Neo4j database
# delete all nodes and relationships
sudo docker exec -ti $(sudo docker ps --format '{{.Names}}') bin/neo4j-shell -c "MATCH (n) DETACH DELETE n;"
echo Stopping Neo4j Docker container
# could also use sudo docker ps --format '{{.ID}}'
# but that would assume that there is only a single Neo4j container running
sudo docker stop $(sudo docker ps -q --filter ancestor=neo4j:3.3)
echo Now removing graph.db labels and property keys
# remove all hanging labels and property kesys
sudo rm -rf neo4j/data/databases/graph.db
sudo docker run --rm --publish=7474:7474 --publish=7687:7687 --volume=$HOME/neo4j/data:/data --volume=$HOME/neo4j/logs:/logs --volume=$HOME/neo4j/import:/var/lib/neo4j/import --volume=$HOME/neo4j/conf:/var/lib/neo4j/conf \
neo4j:3.3
You overcame a perplexing Gotcha related to DETACH DELETE Cypher command and got a graph.db database ready to receive your CSV data file