Loading…

Neo4j interview questions and Answers

By Umesh Singh
Last update: 20 Feb 2020, 20 Questions
Neo4j interview questions

Most Frequently Asked Neo4j interview questions

1. What is neo4j and why it is used for?

It’s an open source, graph database management system used to find the exact relations between data and then extract their true value accordingly. This service is implemented in Java. Due to its excellent performance, responsiveness, flexibility, and scalability; today Neo4j is one of the most business preferred graph database management system in the world.

2. What are the neo4j features?

Neo4j has tons of features for developers. Here are a few best of them:

  • It follows a flexible schema and data model called graph model.
  • It supports full ACID properties.
  • Users can scale the database by increasing the number of reads/writes and volume, without affecting the speed of the query processing and data integrity.
  • High end data safety and reliability.
  • Built-in Neo4j browser web applications to create and retrieve graph data
3. What is the latest version of neo4j?

Neo4j 3.5.3 is the latest version of this graph database management system which was released on 11 February 2019. It came with various significant feature improvements and bug fixes for the developers.

4. Which query language is used for neo4j?

Neo4j uses Cypher as its query language. It’s a declarative graph query language that allows developers for efficient and expressive querying and updating various properties of a graph. It’s a simple yet compelling language.

5. What is a node in neo4j?

In Neo4j, Node is a record or data present in a graph database. Here the CREATE statement is used by the developers to create a Node. Users can use the CREATE statement to create things such as create a single node/multiple nodes, create a node with a label/various labels, create a node with properties and returning the created node.

6. Explain neo4j vs. MongoDB?
S.no Neo4j MongoDB
1. It’s an open source graph database. It’s a document storage
2. The Implementation language here is Java & Scala. The implementation language is C++ here.
3. Neo4j has triggers. It has no triggers.
8. How are a file stored in neo4j?

In Neo4j, the files are storage persisted for long term durability. All the data related file are located inside the Neo4j data directory - data/databases/graph.DB (v3.x+) by default.

9. What do you mean by CQL and how to execute CQL commands in Neo4J?

In Neo4j, CQL or Cypher Query Language is a query language or Neo4j Graph Database, CQL is a declarative pattern machining language which follows SQL like syntax. CQL has read, write and general clauses. It is used to define properties of a relationship or a node.

10. Explain the difference between the Neo4J Graph Database and MySQL Database?
S.no Neo4J MySQL
1. It’s an open source graph database. It’s an open source relational database management systems.
2. Implementation language: Java & Scala. Implementation language:C & C++.
3. Server operating systems are Linux, OS X, Solaris, and Windows. Server operating systems are FreeBSD, Linux, OS X, Solaris, and Windows.
4. Doesn’t support XML. Supports XML.
11. What is object Cache in Neo4J?

In Neo4j, the object cache caches individual relationships and nodes and respectively their properties in a form which is optimized for traversal of the graph. Here contents of this cache are objects with a representation geared towards the Neo4j supporting object API and graph traversals.

12. Explain neo4j index?

In Neo4j, an index is a redundant copy of data in the database purposed of making related data searches more efficient. It comes with the cost of additional storage space and slower writes, so deciding what to index and what not to is a crucial and often non-trivial task for users.

14. What is match command in neo4j and why it is used?

The MATCH command allows developers to specify patterns that Neo4j will search for in the database. This is the original way of getting data into the current set of buildings. It’s often paired with a WHERE clause which predicates or adds restrictions to the MATCH command.

15. List some neo4j commands?
  • Neo4j CQL MATCH command – used to get data about nodes and properties

          MATCH

          (

           <node-name >:<label-name>

          )

  • Delete all nodes and relationships command:

 

16. How to create a new database in neo4j?

To create a new database in Neo4j without removing your existing one, users can directly edit the neo4j.conf file in their conf directory of their $NEO4J_HOME. Search dbms.active_database= and replace it with your desired name and restart the program again. A new database will be created now.

17. How to delete node neo4j?

To delete a node in Neo4j, we have to use the DELETE clause. It also can be used to delete

relationships or paths. The syntax will be as following to delete a single node:

MATCH (n:Person { name: 'UNKNOWN' })

DELETE n

To delete all nodes:

MATCH (n)

DETACH DELETE n

20. How to use set clause in neo4j?

The Set clause in Neo4j can be used to add new properties to an existing relationship or node. It can

also be used to update or add existing properties values. To set a property in a node, here is
 

Example

                                                    

syntax:-

MATCH (node:label{properties . . . . . . . . . . . . . . })

SET node.property = value

RETURN node