NeoGraphManager

NeoGraphManager is a module to do the most common operations using Neo4j graph db.

Refer to the file simple Graph example or the unit tests on how to use the NeoGraphManager apis.

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Prerequisite

Install Neo4j Server on Ubuntu

Use the following commands to install neo4j community edition on Ubuntu based distro.

wget -O - https://debian.neo4j.com/neotechnology.gpg.key | sudo apt-key add -
echo 'deb https://debian.neo4j.com stable latest' | sudo tee /etc/apt/sources.list.d/neo4j.list
sudo apt update
sudo apt install neo4j

If you want to set default database to something other than neo4j, you can edit the file /etc/neo4j/neo4j.conf and change the following lines

# The name of the default database
dbms.default_database=neo4j

To start the service, use the command

$ sudo service neo4j start

Use Neo4j Docker container

Pull the latest Neo4j 4.0 Docker image

$ docker pull neo4j 

Start the Neo4j container

$ docker-compose up -d neo4j

Install dependencies

pip install -r ./requirements.txt

Browse the database manager

http://127.0.0.1:7474/browser/

Use the credentials username neo4j and password:password

Try connecting with bolt settings bolt://0.0.0.0:7687 and bolt://localhost:7687

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Drivers

• Python : py2neo

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Cipher Query Language(CQL)

Neo4j Cipher Query Language is a query language for Neo4j Graph Database.

Here's a short intro to using CQL:

The following Cypher commands are used on the system database to manage multiple databases:

• SHOW DATABASES : Show the name and status of all the databases.
• SHOW DEFAULT DATABASE : Show the name and status of the default database.

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Select the default database and run the following commands in neo4j browser

• Delete any pre-existing nodes if required

MATCH (n) DETACH DELETE n

• Creating a few nodes of type Person

create (bbc:Person {name: 'BBC'})

• Read the node

MATCH (bbc:Person {name: 'BBC'}) RETURN bbc

• We can create a relationship between two Person nodes using the following command

CREATE (granddad:Person {name: 'Grand Dad', age:60})-[r:PARENT_OF]->(dad:Person {name: 'Dad', age:40})-[r2:PARENT_OF]->(son:Person {name: 'Son', age:5})

• Next, we will add two additional nodes Grand Mom and Mom and link it to the existing Dad and Son nodes

CREATE (grandmom:Person {name: 'Grand Mom', age:55})
CREATE (mom:Person {name: 'Mom', age:38})

MERGE (gm:Person {name: 'Grand Mom'})
MERGE (d:Person {name: 'Dad'})
CREATE (gm)-[:PARENT_OF]->(d)

MERGE (m:Person {name: 'Mom'})
MERGE (s:Person {name: 'Son'})
CREATE (m)-[:PARENT_OF]->(s)

That should establish the relationship.

• Get a list of person and their relationships

MATCH (p:Person)-[r:PARENT_OF]->(c:Person) RETURN p, c LIMIT 25

MATCH (n) WHERE EXISTS(n.name) RETURN DISTINCT "node" as entity, n.name AS name LIMIT 25 UNION ALL MATCH ()-[r]-() WHERE EXISTS(r.name) RETURN DISTINCT "relationship" AS entity, r.name AS name LIMIT 25

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References

• Medium: Py2neo v4: The Next Generation
• Graph Databases for Python Users
• Neo4j Browser
• The Py2neo v4 Handbook
• Neo4j Cipher Query Language