Créer des données avec Cypher CREATE

In this lesson, you'll learn how to add new data to your Neo4j graph database using the CREATE clause in Cypher, the query language for Neo4j.

We'll cover creating individual nodes, adding properties, and defining relationships between them. Let's get started!

The simplest way to add a node is with CREATE followed by parentheses (). Inside the parentheses, you can give your node a variable name (like n) for later reference in the same query.

Try running this basic example:

Nodes usually represent real-world entities, like a 'Person' or a 'Movie'. We use labels to categorize nodes. Labels are defined after the node variable using a colon :.

It's good practice to always use labels for better organization and querying.

Nodes often have attributes that describe them. These are called properties. Properties are key-value pairs enclosed in curly braces {} after the label.

• Keys are strings (like name).
• Values can be strings, numbers, booleans, or lists.

You can create several nodes in a single CREATE statement by separating them with a comma ,. This is efficient when adding related data.

Here, we're creating two different types of nodes at once:

Relationships define how nodes are connected. They are directional and always connect two nodes. Their syntax looks like an arrow ()-[]->().

• () for nodes.
• -[]-> for a directed relationship.
• -[]- for an undirected relationship (less common).

To create a relationship between nodes that already exist, you first need to MATCH them. Then, you can use CREATE to define the relationship.

Relationships also have a type (e.g., ACTED_IN) and can have properties.

Just like nodes, relationships can also have properties. These properties describe the relationship itself, not the nodes it connects.

For example, an ACTED_IN relationship might have a role property.

One of the most powerful features of CREATE is the ability to define new nodes and their relationships in a single statement. This helps build complex graph patterns efficiently.

Here, we create a new 'Person' and a new 'City', connecting them with a LIVES_IN relationship.

Let's combine what we've learned to build a small graph for a fictional 'Project' and 'Team' members:

• Create a Project node.
• Create two Person nodes.
• Connect the Persons to the Project with WORKS_ON relationships, each with a role property.

Which of the following Cypher statements correctly creates a new node labeled Product with a name property of 'Laptop' and a price of 1200?

Great job! You've learned the fundamentals of creating data in Neo4j using the Cypher CREATE clause.

• You can create nodes with labels and properties.
• You can define directional relationships between nodes.
• You can even create nodes and relationships in a single statement.

Next, you'll learn how to find and retrieve this data using the MATCH clause!