50+ Best Neo4j Interview Questions and Answers

Last updated on 17th Nov 2021, Blog, Interview Questions

If you are a Java expert and like to work on database management, then learning Neo4j will provide you with an edge in your expert profession. As a Neo4j developer, you will be trained in Graph database management systems, and you will be able to extract the needed data from the given information. ACTE will give you necessary information about the Graph platform, training centers that teach Neo4j, and the need for Neo4j in many enterprises. There are many businesses that have a large amount of unorganized data and they do not know how to make an informative extract from this data. Such businesses are looking to recruit Neo4j developers and are ready to pay them abundantly. You can browse through these job possibilities on ACTE and you can also read the Neo4j job interview questions and answers that will assist you to get hired easily in a reputed company.

1. What is Neo4j sandbox?

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

2. Is Neo4j better than MongoDB?

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

3. Why is Neo4j so popular?

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

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

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

5. What is Neo4j?

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

6. What is Neo4j and how does it work?

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

7. Who uses graph DB?

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

8. What is NoSQL vs SQL?

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

9. What are the famous XML databases?

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

10. What is Neo4j architecture?

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11. How fast is Neo4j?

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

12. Is Neo4j enterprise free?

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

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

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

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

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Neo4j using Cypher query language, which is unique to Neo4j. Traversing the graph requires knowing where you want to begin (Start), the rules that allow traversal (Match) and what data you are expecting back (Return). The basic query consists of:

• START n
• MATCH n-[r]- m
• RETURN r;

15. Mention how indexing is done in Neo4j?

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

START n=node:node_auto_index(name=’abc’) RETURN n

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

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

Client real IP address and not the proxy one

Login failure or attempt success information

Timestamp

17. Is Neo4j a tool?

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

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

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The syntax for MATCH command is:

• Match
• ( “node-name>: )

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

19. Mention the IN Operator syntax in Neo4i?

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

“IN[ Collection-of-values]”

20. Define Neo4j graph platform?

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21. Is Neo4j the best graph database?

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Neo4j — “Open-source graph database”

Created in 2007, Neo4j is ranked as the #1 graph database by db-engines.com.

22. How popular is Neo4j?

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Graph DBMS are designed to model and explore relationships in data in a way not efficiently possible in other types of DBMS (including relational systems).

Graph DBMS increased their popularity by 500% within the last 2 years.

23. Are graph databases worth it?

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

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

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You use “$” prompt to run all CQL commands in Neo4j.

25. What is the difference between Neo4j Vs MongoDB?

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

26. List some Neo4j commands?

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

• Match
• ( “node-name>: )

Delete all nodes and relationships command:

27. What is Graphdb used for?

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

28. What is Neo4j Wikipedia?

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

29. Where is the graph database used?

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

30. Describe a mastering highly distributed architecture?

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31. Does Facebook use a graph database?

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

32. How do I start Neo4j?

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

33. How to use set clauses in neo4j?

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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

34. In Which Language Neo4g Is Written?

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Neo4J is written and implemented in Java language.

35. Why should I use a graph database?

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

36. Is AI a knowledge graph?

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

37. When should I use MongoDB?

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

38. Is MongoDB free to use?

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

39. Is MongoDB better than SQL?

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

40. How is Neo4j exploding?

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41. Is MongoDB a NoSQL?

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

42. What is SQL data?

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SQL (pronounced “ess-que-el”) stands for Structured Query Language. … SQL statements are used to perform tasks such as update data on a database, or retrieve data from a database. Some common relational database management systems that use SQL are: Oracle, Sybase, Microsoft SQL Server, Access, Ingres, etc.

43. How does Neo4j store relationships?

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

44. How much data can Neo4j handle?

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Neo4j 3.0 for Giant Graphs The centerpiece of Neo4j’s architecture overhaul is a redesigned data store. Dynamic pointer compression expands Neo4j’s available address space as needed, making it possible to store graphs of any size. That’s right: no more 34 billion node limits!

45. Is Hadoop a graph database?

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

46. When should I use Neo4j?

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

47. Does Google have a graph database?

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

48. Does Microsoft have a graph database?

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

49. What are graph databases not good for?

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

50. Describe Neo4j modules with rules integration?

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

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The role of building blocks:

• Nodes: They are entities
• Relationship: It connects entities and structure domain
• Properties: It consists of meta-data and attributes
• Labels: It group nodes by role

52. Are graph databases the future?

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

53. Can you store images in Neo4j?

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You have several options: As @Christophe Willemsen suggested you, save the image on disk or on a web site and reference it using a URL. Save it in byte[] array as a property. Save the image in base64 using a Data URI (as String).

54. Is Neo4j scalable?

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

55. What is sharding in Neo4j?

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Neo4j sharding contains all of the fabric graphs (instances or databases) that are managed by a coordinating fabric database. The fabric database is actually a virtual database that cannot store data, but acts as the entrypoint into the rest of the graphs.

56. What is Neo4j used for?

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

57. Is Elastic a graph database?

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

58. Who invented the graph database?

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In this interview with Forbes, Neo4j CEO Emil Eifrem explains how he invented the term “graph database” and developed it into a new market category.

59. Why are graph databases the future?

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

60. How neoMC integrated with Neo4j?

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61. Why is Neo4j popular?

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

62. What problems do graph databases solve?

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

63. What companies use graph databases?

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

64. What is graph SQL?

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

65. What is CuGraph?

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

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

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

67. Do social networks use graph databases?

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

68. Where did the name Neo4j come from?

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

69. When was Neo4j founded?

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

70. When Combining Kafka and Neo4j?

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71. What language does Neo4j use?

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

72. What are the disadvantages of Neo4j?

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

73. What is a Neo4j relationship?

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

74. What is disadvantage of NoSQL *?

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Disadvantages of NoSQL databases

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

75. Is SQL an ETL tool?

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

76. Is Neo4j an acid?

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

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

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

78. What is graph processing?

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

79. What is Neo4j good for?

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

80. Describe an image Neo4j streams?

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81. Does Google use Neo4j?

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“We’re delighted to partner with Neo4j, and we look forward to adding Neo4j for Google Cloud as our first graph database managed service. We share a commitment to a robust open source community that encourages innovation and provides the best possible outcomes for customers,” said Ichhpurani.

82. What is Neo4j ETL?

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

83. When would you use a graphical database?

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

84. What is Neo4j Fabric?

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

85. How does Neo4j replicate data?

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

86. What is the Kibana graph?

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

87. How do I start a Neo4j database?

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

88. How does a graph database work?

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

89. Is Neo4j a good database?

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

90. Define Neo4j physical architecture?

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91. Why is graph database important?

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All relationships are equally important and easily discoverable, making it easier to make associations and form theories about your data. A graph database transforms a complex web of dynamic data into meaningful (and understandable) relationships to help deliver real-time insight and action.

92. What is Gremlin API?

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

93. Define spring data Neo4j?

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