Getting Started Neo4j with Scala : An Introduction

Earlier we used Relational Database for storing the data but there we store data in predefined table and than we define foreign key for references between tables or rows. We are using this in present time also. Now when we talk about the graph database, we stored data in the nodes. Graph database provides us flexibility to arrange data in easy way. When we transform from Relational Database Management System to Graph Database, Here are some transformation :

SELECT c.customer_id , c.customer_name FROM customer AS c WHERE c.customer_city = 'Delhi';

Match (c: customer)
WHERE c.customer_city = 'Delhi'
RETURN c.customer_id , c.customer_name ;

Match (c: customer{customer_city : 'Delhi'})
RETURN c.customer_id , c.customer_name ;

libraryDependencies += "org.neo4j.driver" % "neo4j-java-driver" % "1.0.4"

Create Driver and Session :

val driver = GraphDatabase.driver("bolt://localhost/7687", AuthTokens.basic("anurag", "@nurag06"))
val session = driver.session

case class User(name: String, last_name: String, age: Int, city: String)

Create a Node :

val script = s"CREATE (user:Users {name:'${user.name}',last_name:'${user.last_name}',age:${user.age},city:'${user.city}'})"
val result = session.run(script)

Retrieve all Node :

val script = "MATCH (user:Users) RETURN user.name AS name, user.last_name AS last_name, user.age AS age, user.city AS city"
val result = session.run(script)

Update a Node :

val script =s"MATCH (user:Users) where user.name ='$name' SET user.name = '$newName' RETURN user.name AS name, user.last_name AS last_name, user.age AS age, user.city AS city"
val result = session.run(script)

Delete a Node :

val script =s"MATCH (user:Users) where user.name ='$name' Delete user"
val result = session.run(script)

val nameOfFriends = "\"" + userList.mkString("\", \"") + "\""
val script = s"MATCH (user:Users {name: '${user_name}'}) FOREACH (name in [${nameOfFriends}] | CREATE (user)-[:$relation_name]->(:Users {name:name}))"
session.run(script)

Here we send a user’s name ‘Anurag’, List of Friend (“Sandy”, “Manish”, “Shivansh”) and relation between them is ‘Friends’.

Now we create two more node as a friend of ‘Sandy’.

Now we want to know the Friends of Friends. Here is the Cypher:

val script = s"MATCH (user:Users)-[:$relation_name]-(friend:Users)-[:$relation_name]-(foaf:Users) WHERE user.name = '$user_name' AND NOT (user)-[:$relation_name]-(foaf) RETURN foaf"
session.run(script)

Result For this Cypher is :

For Deleting all relation’s record, we can use this Cypher:

val script = s"MATCH (n)-[relation:$relation_name]->(r) DELETE relation"
session.run(script)

So this is the basic idea that how we can use Neo4j with scala.

I hope it will help you to start with Graph Database(Neo4j). 🙂

You can get the above working example from the github repo, checkout : GitHub

Thanks.

Reference:

1. Neo4j: SQL to Cypher