Adding specific node labels

Introduction

In this lesson, you will learn how to refactor your graph by adding specific node labels to improve query performance and semantic clarity.

Labels allow you to categorize nodes and relationships in your graph, making it easier to query and understand the structure of your data.

By adding specific labels to nodes, you can optimize query performance by reducing the search space and improving index utilization.

Managers

Currently, all employees are represented with the Employee label.

A manager can only be identified by the existence of a REPORTS_TO relationship.

mermaid

Employee REPORTS_TO Employee

graph TD
    Employee -->|REPORTS_TO| Manager
    
    Employee(("<b>Employee</b>"))
    
    Manager(("<b>Employee</b><br /><b><i>Manager</i></b>"))

Finding Managers

This query traverses all the Employee nodes and the REPORTS_TO relationships to find the managers.

cypher

Find the managers

MATCH (e:Employee)-[:REPORTS_TO]->(manager:Employee)
RETURN manager.firstName

By adding a Manager label to the manager nodes, you can optimize this query.

Adding a Manager label

Set a Manager label to the Employee nodes that have an incoming REPORTS_TO relationship:

cypher

Set Manager label

MATCH (e:Employee)-[:REPORTS_TO]->(manager:Employee)
SET manager:Manager
RETURN manager

Query the Manager label

You can now find all managers by querying for nodes with the Manager label:

cypher

Find all managers

MATCH (manager:Manager)
RETURN manager.firstName

Compare the PROFILE of the original query and the refactored query to see the performance difference.

Removing labels

You can remove a label from a node using the REMOVE clause. For example, to remove the Manager label from all nodes:

cypher

Remove Manager label

MATCH (e:Employee)-[:REPORTS_TO]->(manager:Employee)
REMOVE manager:Manager
RETURN manager

Adding a ProductDiscontinued label

Your challenge is to create an ProductActive label.

Not all products are still available for sale. The discontinued property on the Product nodes indicates whether a product has been discontinued or not.

cypher

Find all discontinued products

MATCH (p:Product)
WHERE p.discontinued = true
RETURN p.productName

To complete the challenge you will need to:

Create a Cypher query to identify the active products.
Update the query to SET a new ProductActive label on the active products.
Write a new query to find all active products using the new ProductActive label.

Profile the queries before and after to see the performance difference.

Click to reveal the solution

You can identify the active products by checking for discontinued = FALSE:
cypher
Find active products
```
MATCH (p:Product)
WHERE p.discontinued = false
RETURN p.productName
```

You can set the ProductActive label on the active products:

cypher

Set the label

MATCH (p:Product)
WHERE p.discontinued = false
SET p:ProductActive
RETURN p.productName

Query for active products using the new label:
cypher
Find <code>ProductActive</code> nodes
```
MATCH (p:ProductActive)
RETURN p.productName
```

Finding discontinued products

To find all discontinued products, you can query for Product nodes and do not have the ProductActive label:

cypher

Find discontinued products

MATCH (p:Product&!ProductActive)
RETURN p.productName

Lesson Summary

In this lesson, you learned about adding specific node labels to improve query performance and make your graph model more semantically clear.

In the next lesson, you will learn about adding indirect relationships between nodes.

Neo4j Management, Optimization, and Refactoring Workshop

Setup Neo4j Aura

Aura Administration

Query Performance

Graph refactoring

Adding specific node labels

Introduction

Managers

Finding Managers

Adding a Manager label

Query the Manager label

Adding a ProductDiscontinued label

Lesson Summary

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