Graph Data Modelling

Graph data modelling is the process of designing your data structure using nodes, relationships, properties, and labels. A well-designed graph model makes queries intuitive, performant, and easy to evolve.

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The Building Blocks

Nodes

Nodes represent entities — the things in your domain:

• A person, a product, a city, an order, a device
• Nodes can have zero or more labels (e.g., :Person, :Employee)
• Nodes can have zero or more properties (key-value pairs)

(:Person {name: "Alice", age: 30})
(:Product {name: "Laptop", price: 999.99})
(:City {name: "London", country: "UK"})

Relationships

Relationships connect two nodes and represent how entities are related:

• Every relationship has a type (e.g., PURCHASED, LIVES_IN, MANAGES)
• Every relationship has a direction (from one node to another)
• Relationships can have properties

(Alice)-[:PURCHASED {date: "2024-01-15", quantity: 1}]->(Laptop)
(Alice)-[:LIVES_IN {since: 2018}]->(London)

Tip: Relationship types are written in UPPER_SNAKE_CASE by convention.

Properties

Properties are key-value pairs stored on nodes and relationships:

Data Type	Example
String	name: "Alice"
Integer	age: 30
Float	price: 49.99
Boolean	active: true
Date	createdAt: date("2024-01-15")
List	tags: ["graph", "database"]
Point	location: point({latitude: 51.5, longitude: -0.1})

Labels

Labels are tags that categorise nodes:

• A node can have multiple labels: (:Person:Employee:Manager)
• Labels are used for indexing and querying
• Labels are written in PascalCase by convention

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Modelling Principles

1. Nouns Become Nodes

Identify the main entities in your domain and represent them as nodes:

• Customer, Product, Order, Category

2. Verbs Become Relationships

The actions and connections between entities become relationships:

• Customer PLACED Order
• Order CONTAINS Product
• Product BELONGS_TO Category

3. Adjectives and Adverbs Become Properties

Descriptive information goes on properties:

• Customer has a name, email
• The PLACED relationship has a date

4. Think About Your Queries First

Design the graph model based on the questions you need to answer:

Question	Model Implication
"Which products did Alice buy?"	(:Person)-[:PURCHASED]->(:Product)
"Who are Alice's friends?"	(:Person)-[:FRIENDS_WITH]->(:Person)
"Which products do Alice's friends recommend?"	Traverse through friends to their reviews

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Example: E-Commerce Graph