Neo4j: Features, Install, Advantage & More

Mrinal Singh Walia 06 Feb, 2024 • 9 min read

Today, organizations increasingly harness graph analytics to glean insights from vast, intricate data sets. Neo4j, a leading graph database, empowers developers and data scientists with potent tools for building intelligent applications and workflows. This guide aims to aid beginners in Neo4j, from fundamentals, install neo4j to practical concepts. It defines key terms and provides a code example for Neo4j installation and setup. Prior knowledge of Database Systems and Graph Theory is recommended.

This article was published as a part of the Data Science Blogathon.

What is a Neo4j / Graph Database?

Neo4j is a highly scalable graph database management system, purpose-built for storing and traversing relationships in computing. It replaces tables or documents with nodes and relationships in a graph structure for semantic queries.

Key Points

  1. Node-Based Data: Neo4j stores data entities (e.g., users, companies) as nodes.
  2. Relationship Clarity: Edges represent relationships, making data relationships easily understandable.
  3. Flexibility: Data is stored without a predefined model, enabling adaptable analysis.
  4. Relationship Variety: Nodes can have multiple relationships, while edges have start and end nodes, type, and direction.
  5. Common Use Cases: Organizations use Neo4j to extract precise insights from complex queries involving customer and user data.”

Why Graph Database or Neo4j?

In today’s rapidly evolving tech landscape, companies grapple with vast data volumes. Extracting insights and identifying connections within data are paramount. To address this, companies need a database technology that treats relationship details as a primary entity for maximizing data relationships.

Although existing relational databases can manage these relationships, their performance in handling data relationships remains subpar. The solution to many business needs lies in graph databases. They store relationships alongside nodes (data elements) in a more efficient, flexible format. They excel in swiftly navigating data, making them ideal for adapting to evolving business requirements.

Relational Database vs. Graph Database

If you are still stumbling to find the answer to “How does a relational database differ from a graph-based database, the below difference table will help you understand it in a better way:

 Relational DatabaseGraph Database
FormatIt has tables with rows and columns.It has nodes and edges showing relationships among each other.
RelationshipsRelationships are connected across tables where they are established using foreign keys between tables.Considering data, the relationships are represented between edges and nodes.
Complex QueriesRelational databases require complex joins between tables.Graph databases operate quickly and do not require joins.
Top Use-Cases
Relationational databases are widely adopted for transaction applications such as online transactions and accountings.
Graph databases are mainly used for relationship-heavy use cases, including fraud detection and recommendations engines.

Advantages Of Neo4j

As we all know Graph database is the solution to make rapid progress on mission-critical enterprises. Still, there is a list of benefits of using Neo4j. We are going to study that now:

  • It has a simple, flexible, and robust data model. It can be effortlessly adjusted according to your application needs and business demands.
  • It delivers results based on real-time data.
  • It offers high availability for big company real-time applications with transactional contracts.
  • Neo4j is a schema-free database and provides a straightforward representation of connected and semi-structured data.
  • Using Neo4j, you can represent and easily retrieve (traverse/navigate) connected data faster than other databases comparatively.
  • Neo4j feeds a declarative query language (Cypher Query Language) to illustrate the graph visually employing ASCII-art syntax. The commands of this language are straightforward to understand and are humanly readable.
  • Neo4j is fast because more interconnected data is straightforward to retrieve and navigate.
  • Using Neo4j does not need complicated joins to retrieve connected/related data. It is straightforward to retrieve its neighboring node or relationship attributes without joins or indexes.
  • Neo4j provides higher vertical scaling, improved operational characteristics, higher concurrency, and simplified tuning.

Features Of Neo4j

To summarize, until now, we have seen what Neo4j is. Why is Neo4j so popular? Difference between Neo4j and relational database management system, and advantages of Neo4j as a widely used graph database across all enterprises and businesses.

In this section, we will examine a list of significant features of Neo4j:

Data Model With Flexible Schema

Neo4j adheres to the property graph model as its data model. The graph comprises nodes representing entities, and these nodes are interconnected through relationships. Both nodes and relationships store data in key-value pairs, referred to as properties. Neo4j imposes no fixed schema, allowing you to add or remove properties based on your requirements. Additionally, Neo4j provides schema constraints for enhanced data management.

ACID Properties

Neo4j supports rich ACID properties:

  • A: Atomicity
  • C: Consistency
  • I: Isolation
  • D: Durability

Scalability & Reliability

Neo4j allows you to scale the database by increasing the number of reads/writes operations and the volume without impacting the query processing speed and data integrity. It also furnishes permission for replication for data protection and reliability.

Built-in Web applications

Neo4j also offers a built-in Neo4j browser web application that can be utilized to construct and retrieve your graph data.

Indexing & GraphDB

Neo4j sustains Indexes by employing Apache Lucence & follows Property Graph Data Model.

Some Other General Features

  • It provides REST API to work with programming languages such as Java, Spring, Scala, etc.
  • It supports UNIQUE constraints and uses native graph storage along native GPE(Graph Processing Engine).
  • It provides Java Script to work with UI MVC frameworks such as Node JS.
  • Cypher API and Native Java API are the two types of Java API supported by Neo4j. Using these APIs, you can develop robust Java applications.
  • In addition to these, Neo4j supports exporting query data to JSON and XLS format to work with other databases such as MongoDB or Cassandra.

Neo4j Property Graph Data Model

As we saw in the features section, Neo4j follows a property graph data model to store and manipulate its data. This section will discuss some of the critical features and central building blocks of the property graph data model, which are:

Nodes

  • First, it is essential to know that a graph data structure consists of nodes (data entities or discrete objects) represented by relationships.
  • Nodes can have one or more labels to classify their nodes and are represented using circles.

Relationships

  • Relationships represent a link between a source node and a target node. They can be Unidirectional and Bidirectional only (that means it always has a direction). It is only denoted using arrow keys.
  • Relationships must have a type to classify their ties, i.e., “Start Node” or “From Node” and “To Node” or “End Node.”

Properties

  • Nodes and relationships can have properties where they are key-value pairs, further describing them.
Neo4j Graph Database
Source: Neo4j

How To Install Neo4j On Ubuntu?

This section will explain installing and configuring the Neo4j on Ubuntu 20.04 server.

Prerequisites

For setting-up Neo4j, the following setting is recommended:

  • 1GB Ram, 15GB of free storage, and a single-core server
  • All commands should be run in root mode. If you are not in root mode, controls must be followed by the Sudo command. In this tutorial, we will be using the sudo command for your ease.
  • Ubuntu 20.04

Install Neo4j

The official Ubuntu package repositories do not officially include Neo4j in the standard package repository. To install the upstream supported package from Neo4j, we will add the package source pointing to the location of the Neo4j repository. Then we will add the GPG key from Neo4j for confirmation. After that, we will install Neo4j.

Step 1: We start by updating the existing list of packages.

Command

command 2

Step 2: Install neo4j packages

This step will install a few prerequisite packages for HTTPS connections to secure the installation. This application may be already installed in your systems by default. Still, it is safe to run the following command anyways.

Command

Neo4j Graph Database

 

Step 3: Add security GPG key

We will add the security GPG key for the official Neo4j package repository in this step. This key will confirm that you can trust what you are installing is from the official Neo4j upstream repository.

Command

command

Output

OK

Step 4: Add the Neo4j repository to your system’s package manager list.

Command

Neo4j Graph Database

Step 5: Install the Neo4j package

The final phase in this module is to install the Neo4j package and all of its dependencies. It is necessary to mention that this installation will also download and install a compatible Java package to work with Neo4j. So you can enter “Y” to accept this software install. If your system already has Java installed, the installer will skip this stage.

Command

Neo4j Graph Database

Start Neo4j Service

Step 1: Enable neo4j.service

After the installation, Neo4j should be running. However, we need to enable it as a “neo4j.service” service to set it to start on a reboot of the system.

Command

command

Step 2: Use systemctl command

Next, examine Neo4j’s status using the “systemctl” command. This step is essential to verify that everything is working as expected.

Command

Neo4j Graph Database

Testing and Working With Neo4j

Now that you have Neo4j and its dependencies installed on your system and its services started, you are all set to test the DB connection and configure the admin user.

Step 1: Interact with Neo4J

To interact with the Neo4j database on the command line, we will launch the internal utility using the “cypher-shell” command.

Command

cypher shell

Output

output

Initially, you’ll need to provide a username and password, which are set to ‘neo4j’ by default. After successful authentication, you’ll be prompted to update the administrator password according to your preference.

Once the password is updated, you’ll gain access to the interactive ‘neo4j’ prompt. Here, you can interact with the Neo4j database by inserting and querying nodes

Step 2: Use exit command

Use the exit command after setting an administrator password and testing a connection to Neo4j.

Command

Neo4j Graph Database

Output

Bye!

Neo4j CQL: Clauses, Functions, Datatypes, and Operators

As discussed in the earlier section, Neo4j has CQL (Cypher Query Language) as query language. Now we will see some of the clauses, functions, data types, and operators supported in CQL.

Neo4j CQL Clauses

CommandDescription
MATCHSearches data with a specified pattern.
OPTIONAL MATCHFunctions like MATCH but allows null for missing parts.
WHEREAdds conditions to CQL queries.
STARTLocates initial points through legacy indexes.
LOAD CSVImports data from a locally stored CSV file.
CREATECreates nodes, properties, and relationships in the DB.
SETUpdates labels on nodes and properties on nodes/relationships
MERGEChecks if a pattern exists; creates if not.
DELETERemoves nodes, relationships, and paths from the DB.
REMOVEEliminates elements and properties from nodes/relationships.
FOREACHUpdates data within a list.
CREATE UNIQUEMatches and creates a unique pattern.
RETURNSpecifies the query result set.
ORDER BYArranges query output in order (used with RETURN or WITH).
LIMITRestricts result rows to a specific value.
SKIPChains query parts together.
UNWINDExpands a list into rows.
UNIONJoins outcomes of multiple queries.
CALLInvokes a deployed procedure in the database.

Neo4j CQL Functions

TermDescription
StringUsed when working with string literals.
AggregationConducts aggregation operations on CQL query results.
RelationshipUsed to fetch details of relationships, such as start and end nodes.

Neo4j CQL Data Types

Most Neo4j data types are similar to the java language data types. They are also used to define the properties of a node or a relationship.

Data TypeDescription
BooleanDefines boolean values (True, False).
byteDescribes an 8-bit integer.
shortDetermines 16-bit integers.
intDefines 32-bit integers.
longDescribes 64-bit integer.
floatDescribes a 32-bit floating-point number.
doubleExpresses a 64-bit floating-point number.
charRepresents a 16-bit character.
StringRepresents a literal string.

Neo4j CQL Operators

Here are the operators supported by Neo4j CQL:

Operator TypeOperators
Mathematical Operators+, -, *, /, %, ^
Comparison Operators>, <, >=, <=, =
Boolean OperatorsAND, OR, XOR, NOT
String Operators+
List Operators+, IN, [X], [X?..Y]
Regular Expression=~
Matching StringSTARTS WITH, ENDS WITH, CONSTRAINTS

Conclusion

The prime motive behind the launch of the Neo4j graph database was to help users solve many different kinds of business and technical needs. It is simple to use and fits your use-cases whether you depend on graph transactions, market analysis, operational optimizations, or anything else. It has always delivered a seamless experience for integrating additional tools with the rest of your existing system.

Here are a few resources to support your further journey into this tool:

Read more articles on our blog.

Frequently Asked Questions

Q1. What is Neo4j used for?

A. Neo4j is used for managing and querying graph data, making it ideal for applications involving complex relationships like social networks, recommendation engines, and knowledge graphs.

Q2. Is Neo4j SQL or NoSQL?

A. Neo4j is a NoSQL database specifically designed for graph data, not SQL.

Q3. What are the downsides of Neo4j?

A. Downsides of Neo4j include a learning curve, resource-intensive operations on large graphs, and limited support for certain types of queries.

Q4. Is Neo4j still relevant?

A. Neo4j remains relevant for applications requiring complex relationship modeling and querying, as graph databases continue to find use in various industries.

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Mrinal Singh Walia 06 Feb 2024

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