50+ Best Neo4j Interview Questions and Answers

1. What is a Neo4j sandbox?

Ans:

Neo4j Sandbox is the great free way to try out Neo4j without downloading or installing anything locally. It gives access to Neo4j database, Neo4j Bloom, and plugins like a Neo4j Graph Data Science, all hosted online and private. Once sign in can choose which project to be spin up.

2. Is Neo4j better than a MongoDB?

Ans:

MongoDB provides a high speed, high availability, and high scalability.

3. Why is a Neo4j so popular?

Ans:

To summarize, Neo4j is widely used to across all enterprises and businesses, primarily due to its speed, efficiency and an accuracy. Check out a book Seven NoSQL Databases in the Week to learn more about Neo4j and the other popularly used to NoSQL databases such as Redis, HBase, MongoDB, and more.

4. Mention what is difference between Neo4j graph database and MySQL?

Ans:

Neo4j	Mysql
It consists of vertices and also edges. Every vertex or node represent a key value or attribute.	In a relational databases, attributes are appended in a plain table format.
It is possible to store a dynamic content like images, videos, audio.	In a relational databases, such as MySQL, it’s difficult to store the videos, audios, images.

5. What is a Neo4j?

Ans:

Neo4j is open-source, NoSQL, native graph database that provides a ACID-compliant transactional backend for the applications. … This means that a data is stored exactly as whiteboard it, and database uses a pointers to navigate and traverse the graph.

6. What is a Neo4j and how does it work?

Ans:

Neo4j is graph database. A graph database, instead of having a rows and columns, has nodes, edges and properties. It is a more suitable for certain big data and analytics applications than a row and column databases or a free-form JSON document databases for many use cases. A graph database is used to represent a relationships.

7. Who uses a graph DB?

Ans:

A compelling use of a graph databases is in integrating a business’s data from across its estate of a data silos. This generates a considered view of overall landscape, and can be used to an improve insight, for example by enabling “360-degree customer view.”

8. What is a NoSQL vs SQL?

Ans:

SQL databases are more relational, NoSQL databases are the non-relational. … SQL databases are table-based, while a NoSQL databases are document, key-value, graph, or wide-column stores. SQL databases are better for a multi-row transactions, while NoSQL is better for a unstructured data like documents or JSON.

9. What are famous XML databases?

Ans:

The famous XML databases are the Oracle database, MarkLogic exist, MarkLogic Cassandra, and MarkLogic Cassandra exist. Explanation: These xml databases are be programming languages that help in a processing and the manipulation of large amounts of data within the short span of time.

10. Mention a important features of a Neo4J?

Ans:

• Data Representation using the graph model.
• A Reliable ACID transactions.
• A Quick and Durable.
• High-Speed query execution for a traversals.
• Easily accessible by a REST or Java APIs.

11. How fast is a Neo4j?

Ans:

For a simple friends of friends query, Neo4j is 60% faster than a MySQL. For friends of friends of a friends, Neo is a 180 times faster. And for a depth four query, Neo4j is a 1,135 times faster.

12. Is a Neo4j enterprise free?

Ans:

That said, Neo4j Enterprise Edition is also available for a free for a number of uses: Startups with <=50 employees can contact us to receive a free Startup License for the Neo4j Enterprise, and anybody & everybody can get free-for-development use (single-user, local desktop/ single machine) license by a Neo4j Desktop.

13. Mention what are different types of a object caches in Neo4j?

Ans:

Reference caches	High performance caches
With this cache, Neo4j will use as much as to be allocated JVM heap memory as it can hold a nodes and relationships.	It gets an assigned a certain maximum amount of space on a JVM heap and will delete objects whenever it grows a bigger than that.

14. Mention which query language does a Neo4j use and what it consists of?

Ans:

Neo4j using a Cypher query language, which is unique to a Neo4j. Traversing the graph requires knowing where want to begin (Start), the rules that are allow traversal and what data are expecting a back .

15. Mention a how indexing is done in a Neo4j?

Ans:

There was a no indexing in earlier days for the Neo4j, but later on it was introduced with a new feature Automatic Indexes by using a command.

16. Explain how a Neo4j can be helpful in detecting Brute Force Attack?

Ans:

Neo4J allows to save and retrieve a multiple complex relations. The capability of Neo4j to do difficult queries in real time is really helpful in identifying brute force attack much quicker. The most crucial thing in a detecting such attacks is to capture enough information about each requests be like.

• A Client real IP address and not a proxy one.
• Login failure or attempt a success information.
• A Timestamp.

17. Is a Neo4j a tool?

Ans:

Neo4j Bloom is the data exploration tool that visualizes data in a graph and allows users to navigate and query the data without any query language or programming. Users can write a patterns similar to natural language questions to retrieve a data and traverse layers of agraph.

18. Explain what is a MATCH command syntax and what is a rule for using it?

Ans:

Match:

( “node-name>: )

The rule for using a MATCH command is that are cannot use this command alone to fetch a data from the database otherwise it will show invalid syntax error.

19. Mention IN Operator syntax in Neo4i?

Ans:

The IN Operator syntax in a NEO4j would be something like this:

20.What does Neo4J graph node store?

Ans:

A Key-Value Pairs.

21. Is a Neo4j the best graph database?

Ans:

• A Neo4j — “Open-source graph database”.
• Created in a 2007, Neo4j is ranked as #1 graph database by db-engines.com.

22. How popular is a Neo4j?

Ans:

Graph DBMS are designed to a model and explore relationships in data in a way not efficiently possible in the other types of DBMS .DBMS increased their popularity by a 500% within a last 2 years.

23. Are graph databases worth it?

Ans:

Graph databases are very good at a traversing relationships between the small data entities, but not ideally suited to save a lot of properties on a single node or a large values in those properties. For this type of use case, a graph database is not be recommended.

24. Explain how can run a CQL commands in Neo4j?

Ans:

Use “$” prompt to run all the CQL commands in Neo4j.

25. What is difference between a Neo4j Vs MongoDB?

Ans:

Neo4j	MongoDB
A primary database model is a Graph DBMS.	A primary database model is a Document Store.
Implemented in the Java and Scala.	Implemented in the C++ Language.

26. List some of Neo4j commands?

Ans:

Neo4j CQL MATCH command – used to get a data about nodes and properties:

27. What is a Graphdb used for?

Ans:

Graph databases are purpose-built to save and navigate relationships. Relationships are the first-class citizens in graph databases, and most of value of graph databases is derived from these relationships. Graph databases use a nodes to store data entities, and edges to store a relationships between an entities.

28. What is a Neo4j Wikipedia?

Ans:

Neo4j is a graph database management system developed by a Neo4j, Inc. Neo4j is implemented in the Java and accessible from software written in a other languages using the Cypher query language through the transactional HTTP endpoint, or through a binary “Bolt” protocol.

29. Where is a graph database used?

Ans:

Graph databases are the most commonly used for a highly interconnected data, and for situations where a content of the data itself matters less than overall structure. The most straightforward use case for a graph data is for the social networks.

30. What kind of language is a CQL?

Ans:

There are two types of a query languages – Procedural and declarative.CQL is the Declarative Language.

31. Does Facebook use graph database?

Ans:

Facebook’s Social Graph — a database underlying its Graph Search engine an unveiled yesterday– is just one of many graph databases being employed for difficult, connected data.

32. How do start a Neo4j?

Ans:

Neo4j can also be run as Windows service. Install a service with bin\neo4j install-service , and start it with a bin\neo4j start . The available commands for a bin\neo4j are: help , start , stop , restart , status , install-service , uninstall-service , and update-service .

33. How to use a set clauses in neo4j?

Ans:

The Set clause in a Neo4j can be used to add a new properties to an existing relationship or node. It can be used to update or add existing properties values. To set a property in the node, here is:

Example:

• syntax:
• MATCH (node:label{properties . . . . . . . . . . . . . . })
• SET node.property = value
• RETURN node

34. In Which Language a Neo4g Is Written?

Ans:

Neo4J is written and implemented in the Java language.

35. Why should use a graph database?

Ans:

In order to leverage data relationships, organizations need the database technology that stores a relationship information as a first-class entity. Not only do graph databases effectively store a data relationships; they’re also flexible when expanding the data model or conforming to changing a business needs.

36. Is AI knowledge graph?

Ans:

Knowledge Graphs in an Artificial Intelligence. Knowledge graphs, also known as a semantic networks in the context of AI, have been used as a store of world knowledge for the AI agents since the early days of field, and have been applied in all areas of a computer science.

37. When should use a MongoDB?

Ans:

NoSQL databases like a MongoDB are a good choice when data is document-centric and doesn’t fit well into a schema of a relational database, when need to accommodate a massive scale, when rapidly prototyping, and a few other can use cases.

38. Is a MongoDB free to use?

Ans:

Can get started with the MongoDB developer sandbox in a MongoDB Atlas for free with basic configuration options. No credit cards are required to a provision a cluster, and can use it to explore and learn more about the MongoDB Atlas, a database-as-a-service platform from MongoDB.

39. Is a MongoDB better than SQL?

Ans:

MongoDB offers a faster query processing but with increased load and system requirements. Without knowing a purpose of use, it is not possible to classify a SQL Databases or NoSQL Databases like the MongoDB as better or worse than a other. There are different factors that drive a MongoDB vs SQL decision.

40. Mention few other famous graph databases available?

Ans:

• Oracle NoSQL Database.
• Sqrrl Enterprise.
• Graph Story.
• Titan.
• Velocity Graph.
• InfoGrid.
• Bitsy.
• Teradata Aster.
• Oracle Spatial and Graph.
• Info Grid and many more.

41. Is MongoDB a NoSQL?

Ans:

NoSQL databases come in a variety of types including a document databases, key-values databases, wide-column stores, and graph databases. MongoDB is a world’s most popular of NoSQL database.

42. What is a SQL data?

Ans:

SQL stands for a Structured Query Language. … SQL statements are used to perform a tasks such as update data on database, or retrieve data from a database. Some general relational database management systems that use a SQL are: Oracle, Sybase, Microsoft SQL Server, Access, Ingres, etc.

43. How does a Neo4j store relationships?

Ans:

Properties are stored as the linked list of property records, each holding a key and value and pointing to a next property. Every node and relationship references its a first property record. The Nodes also reference a first relationship in its relationship chain. Every Relationship references its start and end node.

44. How much a data can Neo4j handle?

Ans:

Neo4j 3.0 for a Giant Graphs The centerpiece of a Neo4j’s architecture overhaul is a redesigned data store. Dynamic pointer compression expands the Neo4j’s available address space as needed, making it possible to save a graphs of any size.

45. Is Hadoop graph database?

Ans:

Hadoop and Neo4j are both primarily classified as “Databases” and “Graph Databases” tools respectively.

46. When should use a Neo4j?

Ans:

Graph databases help to unify a master data, such as information about the customers, products, suppliers, and logistics. Neo4j allows to organize master data and model it in graph, revealing connections and relationships. Neo4j can provide an important insights so that can make a relevant business decisions.

47. Does a Google have a graph database?

Ans:

A horizontally scalable, a globally consistent, and relational database service. It is an externalization of the core Google database that runs the biggest aspects of a Google, like Ads and Google Play. Enterprise-ready RDF and graph database with an efficient reasoning, cluster and external index synchronization support.

48. Does Microsoft have graph database?

Ans:

Azure Cosmos a DB is the globally distributed, multi-model database service from the Microsoft for mission-critical applications. … Azure Cosmos to DB provides a graph database service by a Gremlin API on a fully managed database service designed for any scale.

49. What are the graph databases not good for?

Ans:

Graph databases are not as useful for an operational use cases because they are not efficient at a processing high volumes of transactions and they are not good at a handling queries that span of entire database.

50. List out some of Neo4J Commands you use?

Ans:

CREATE – To create the node or relationship.

MATCH – To read or retrieve all nodes in a database.

MERGE – Combination of a CREATE and MATCH.

SET – To add or update a properties to new or existing nodes/relationships.

CREATE UNIQUE – To mention a unique constraints in order to avoid the redundant values.

51. Explain a role of building blocks like Nodes, Relationships, Properties and Labels in Neo4j?

Ans:

Nodes: They are be entities.

Relationship: It connects to entities and structure domain.

Properties: It consists of a meta-data and attributes.

Labels: It group nodes by a role.

52. Are a graph databases the future?

Ans:

A Dataversity survey found that a 22.6% of data professionals planned to used graph databases in a future. Gartner now predicts that application of a graph technologies will double annually through a 2022.

53. Can store images in a Neo4j?

Ans:

Save the image on a disk or on a web site and reference it using URL. Save it in byte[] array as the property. Save a image in base64 using a Data URI (as String).

54. Is a Neo4j scalable?

Ans:

Neo4j is fastest path to graph, and is the only enterprise-strength graph database that combines a native graph storage, scalable architecture optimized for speed, and ACID compliance to an ensure predictability of relationship-based queries.

55. What is sharding in a Neo4j?

Ans:

Neo4j sharding contains all of fabric graphs that are managed by the coordinating fabric database. The fabric database is actually virtual database that cannot to store data, but acts as an entrypoint into the rest of graphs.

56. What is a Neo4j used for?

Ans:

Neo4j uses a property graphs to extract added value of a data of any company with great performance and in agile, flexible and scalable way. 1. Performance: Graph databases like Neo4j perform better than a relational (SQL) and non-relational (NoSQL) databases.

57. Is Elastic graph database?

Ans:

Elasticsearch is the full-text search engine. Elasticsearch is able to achieve a fast search responses because it searches index instead of searching a text directly. Graph Database. Graph databases used graph theory to store, map and query relationships.

58. Who invented a graph database?

Ans:

Neo4j CEO Emil Eifrem define how invented a term “graph database” and developed it into the new market category.

59. Why are graph databases the future?

Ans:

Graph databases will effectively save the relationships that exist between a data points, and they are flexible enough to add a new kinds of relationships and adapt the data model to allow a new business requirements. Many converts see a graph databases as a future of online businesses.

60. What is a REMOVE command used for?

Ans:

To remove labels and properties of t a nodes, can use REMOVE.

61. Why is a Neo4j popular?

Ans:

Neo4j is open-source NoSQL graph database that are enables ACID-compliant transactions, supporting a friendly query language. Compared to the relational databases, Neo4j offers a superior performance in retrieving data based on a relations to various levels, and provides cluster support and also runtime failover.

62. What problems are do graph databases solve?

Ans:

Problems around Centrality, Clustering, and Influence are the another typical use case for a graph databases. Examples for these types of problems need to finding the most influential person in Twitter network, identifying critical pieces of infrastructure, or locating groups of entities within a data.

63. What companies use a graph databases?

Ans:

Neo4j is a leading graph database technology that drives an innovation and competitive advantage at Airbus, Comcast, eBay, NASA, UBS and more.

64. What is a graph SQL?

Ans:

SQL Graph Database A graph is the collection of node and edge tables. For example, a Person node table holds all a Person nodes belonging to a graph. Similarly, edge table is a collection of similar types of the edges.

65. What is a CuGraph?

Ans:

CuGraph is the collection of graph algorithms implemented over a Nvidia GPUs. … There are many graph algorithms are around, and each algorithm can provide the insights for various data analysis scenarios. When a cuGraph’s first official release, 0.6, came out in a late March, it already contained more algorithms, including a PageRank.

66. Explain how can create/delete databases in a Neo4j?

Ans:

To delete/remove entire graph directory and can use a command rm –rf data/* as such Neo4j is not storing for anything outside that.

67. Do social networks use a graph databases?

Ans:

Graph data models are widely used in a various areas of computer science such as bioinformatics, graph databases, social networks and static code analysis. One of problems in a graph data analysis is querying for a specific paths.

68. Where did name a Neo4j come from?

Ans:

The ‘j’ is from a word ‘jätteträd’, literally “giant tree”, and was used to indicate a huge data structures that could now be stored. Incidentally the ‘neo’ portion of name is a nod to a Swedish pop artist Linus Ingelsbo, who goes by a name NEO.

69. When was a Neo4j founded?

Ans:

CEO and co-founder of Emil Eifrem said that Neo4j, which was founded back in a 2007, has hit its growth stride in a recent years given the rising popularity of a graph-based analysis.

70. What is difference between a REMOVE and DELETE commands?

Ans:

The main difference is REMOVE is fora labels and properties of nodes, whereas a DELETE is to remove the nodes and relationships.

71. What language does a Neo4j use?

Ans:

Cypher is a Neo4j’s graph query language that allows users to save and retrieve data from a graph database. Neo4j wanted to make a querying graph data simple to learn, understand, and use for the everyone, but also incorporate a power and functionality of the other standard data access languages.

72. What are disadvantages of a Neo4j?

Ans:

• A Neo4j Drawbacks or Limitations.
• AS of a Neo4j 2.1. 3 latest version, it has a limitation of supporting number of a Nodes, Relationships and Properties.
• It does not support a Sharding.

73. What is Neo4j relationship?

Ans:

Advertisements. In a Noe4j, a relationship is an element using which are connect two nodes of graph. These relationships have a direction, type, and a form patterns of data.

74. What is the disadvantage of NoSQL ?

Ans:

Compatibility issues with the SQL instructions. Support for a work query issues in a NoSQL database is more complicated. A Lack of standardization. There are many NoSQL databases and there is still no standard like ones that exist in a relational databases.

75. Is SQL ETL tool?

Ans:

The difference here is that SQL is the query language, while an ETL is an approach to extract, process, and load data from a multiple sources into a centralized target destination. When working in the data warehouse with SQL, can: Create a new tables, views, and stored procedures within a data warehouse.

76. Is a Neo4j an acid?

Ans:

Neo4j is open-source, NoSQL, native graph database that offers an ACID-compliant transactional backend for the applications.

77. What are some options for loading a data into Neo4j?

Ans:

There are two ways to import a data from CSV files into Neo4j: by neo4j-admin import or a LOAD CSV . If want to do batch imports of large amounts of data into the Neo4j database from CSV files, use an import command of a neo4j-admin .

78. What is a graph processing?

Ans:

A graph processing framework (GPF) is the set of tools oriented to process graphs. Graph vertices are used to model data and an edges model relationships between the vertices. Since real graphs can be a large, complex, and dynamic, GPFs have to deal with a three challenges of data growth: volume, velocity, and variety.

79. What is a Neo4j good for?

Ans:

Here’s what need to know about a graph database limitations. Graph databases are not as useful for the operational use cases because they are not efficient at a processing high volumes of transactions and they are not good at handling queries that span an entire database.

80. What is a object Cache in Neo4J?

Ans:

In order to improve performance of a graph traversals, Object Cache is used to cache a nodes and their properties.

81. Does a Google use Neo4j?

Ans:

Share a commitment to the robust open source community that encourages an innovation and provides a best possible outcomes for the customers,” said Ichhpurani.

82. What is a Neo4j ETL?

Ans:

Neo4j ETL reveals a data connections within the tabular data stored in an RDBMS and delivers an exceptional initial and ongoing experience moving data into a Neo4j graph database. With Neo4j ETL can: Connect to a popular databases by JDBC. Use graphical interface to adjust values.

83. When would use a graphical database?

Ans:

Graphical Database Use Cases Graphical databases work best if a data that are working with is very connected and should be represented by linking them or referring to the other data, usually through many relationships. Again, a social network is be useful example.

84. What is a Neo4j Fabric?

Ans:

Neo4j Fabric is the tool for storing and retrieving data ina multiple databases, located in one or many Neo4j DBMS(s), with the single Cypher query.

85. How does a Neo4j replicate data?

Ans:

In Neo4j, replication across a data centers is supported only by standard replication mechanisms. Replica Writes: Replicated databases typically provide configuration options that are enable an application to specify a number of replicas to write to, and in some cases which replicas to write to.

86. What is a Kibana graph?

Ans:

Graphedit. The graph analytics features enable to discover how items in Elasticsearch index are related. Can explore a connections between indexed terms and see which connections are most meaningful. This can be useful in the variety of applications, from a fraud detection to recommendation engines.

87. How do start a Neo4j database?

Ans:

Neo4j can also be run as Windows service. Install a service with a bin\neo4j install-service , and start it with a bin\neo4j start . The available commands for a bin\neo4j are: help , start , stop , restart , status , install-service , uninstall-service , and update-service .

88. How does graph database work?

Ans:

Graph databases work by a storing the relationships along with a data. … A graph database not only saves the relationships between objects in a native way, making queries about a relationships fast and easy, but allows to include a various kinds of objects and different kinds of relationships in a graph.

89. Is Neo4j good database?

Ans:

Performance: Graph databases such as a Neo4j perform better than a relational (SQL) and non-relational (NoSQL) databases. The key is that, even though data queries increase an exponentially, performance of a Neo4j does not drop, compared to what happens with the relational databases such as MySQL.

90. What are types of Object Cache in a Neo4J?

Ans:

• A Reference Cache.
• A High-Performance Cache(HPC.

91. Why is a graph database important?

Ans:

All relationships are equally important and simply discoverable, making it simpler to make associations and form the theories about data. A graph database transforms a difficult web of dynamic data into a meaningful relationships to help a deliver real-time insight and action.

92. What is a Gremlin API?

Ans:

It is multi-model database and supports a document, key-value, graph, and column-family data models. Azure Cosmos DB’s Gremlin API is built based on a Apache TinkerPop, a graph computing framework. The Gremlin API in an Azure Cosmos DB uses a Gremlin query language.

93. Command for an updating properties or adding a new properties to existing relationships?

Ans:

SET is a command used to update or add the properties to an existing relationships.

94. Brief a Neo4j CQL LIMIT clause?

Ans:

For filtering or limiting a number of rows that return by query, can use a Neo4j CQL LIMIT clause.

95. What is a IN Operator syntax?

Ans:

IN a Operator Syntax: IN[ ].

96. CREATE UNIQUE is be used for?

Ans:

CREATE UNIQUE used for the fixing a graph structures.

97. Which is fastest to handle a graphs, MYSQL or Neo4j?

Ans:

To handle a graphs Neo4j is a fastest one compared to a MYSQL.

98. Which architecture allows for the remote server?

Ans:

REST architecture, that allows neo4j for a remote servers.

99. Explain how Neo4j stores are primitive array?

Ans:

Neo4j stores a primitive array in the compressed way in order to save a space on disk, to do that it uses a “bit saving” algorithm.

100. Neo4j OLTP or OLAP?

Ans:

Titan, OrientDB, Neo4j are the examples of OLTP tools. OLAP systems instead perform a complex analysis which involved an extremely large graphs.