DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports
Events Video Library
Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
View Events Video Library
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks

Mobile Database Essentials: Assess data needs, storage requirements, and more when leveraging databases for cloud and edge applications.

Full-Stack Observability Essentials: Explore the fundamentals of system-wide observability and key components of the OpenTelemetry standard.

Monitoring and Observability for LLMs: Datadog and Google Cloud discuss how to achieve optimal AI model performance.

Automated Testing: The latest on architecture, TDD, and the benefits of AI and low-code tools.

Related

  • Externalize Microservice Configuration With Spring Cloud Config
  • Build a Java Microservice With AuraDB Free
  • Working With Neo4j Graph Database
  • How to Convert XLSX to CSV in Java

Trending

  • JWT Token Revocation: Centralized Control vs. Distributed Kafka Handling
  • Resistance to Agile Transformations
  • Microservices With Apache Camel and Quarkus
  • Exploring Different Continuous Integration Servers: Streamlining Software Development
  1. DZone
  2. Data Engineering
  3. Databases
  4. Neo4j: LOAD CSV - Handling Empty Columns

Neo4j: LOAD CSV - Handling Empty Columns

Mark Needham user avatar by
Mark Needham
·
Aug. 25, 14 · Interview
Like (1)
Save
Tweet
Share
8.91K Views

Join the DZone community and get the full member experience.

Join For Free

A common problem that people encounter when trying to import CSV files into Neo4j using Cypher’s LOAD CSV command is how to handle empty or ‘null’ entries in said files.

For example let’s try and import the following file which has 3 columns, 1 populated, 2 empty:

$ cat /tmp/foo.csv
a,b,c
mark,,
load csv with headers from "file:/tmp/foo.csv" as row
MERGE (p:Person {a: row.a})
SET p.b = row.b, p.c = row.c
RETURN p

When we execute that query we’ll see that our Person node has properties ‘b’ and ‘c’ with no value:

==> +-----------------------------+
==> | p                           |
==> +-----------------------------+
==> | Node[5]{a:"mark",b:"",c:""} |
==> +-----------------------------+
==> 1 row
==> Nodes created: 1
==> Properties set: 3
==> Labels added: 1
==> 26 ms

That isn’t what we want – we don’t want those properties to be set unless they have a value.

TO achieve this we need to introduce a conditional when setting the ‘b’ and ‘c’ properties. We’ll assume that ‘a’ is always present as that’s the key for our Person nodes.

The following query will do what we want:

load csv with headers from "file:/tmp/foo.csv" as row
MERGE (p:Person {a: row.a})
FOREACH(ignoreMe IN CASE WHEN trim(row.b) <> "" THEN [1] ELSE [] END | SET p.b = row.b)
FOREACH(ignoreMe IN CASE WHEN trim(row.c) <> "" THEN [1] ELSE [] END | SET p.c = row.c)
RETURN p

Since there’s no if or else statements in cypher we create our own conditional statement by using FOREACH. If there’s a value in the CSV column then we’ll loop once and set the property and if not we won’t loop at all and therefore no property will be set.

==> +-------------------+
==> | p                 |
==> +-------------------+
==> | Node[4]{a:"mark"} |
==> +-------------------+
==> 1 row
==> Nodes created: 1
==> Properties set: 1
==> Labels added: 1
CSV Database Neo4j

Published at DZone with permission of Mark Needham, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Related

  • Externalize Microservice Configuration With Spring Cloud Config
  • Build a Java Microservice With AuraDB Free
  • Working With Neo4j Graph Database
  • How to Convert XLSX to CSV in Java

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 3343 Perimeter Hill Drive
  • Suite 100
  • Nashville, TN 37211
  • support@dzone.com

Let's be friends: