Neo4j: MATCH, CREATE, MERGE

Introduction

This lesson explores the essential Neo4j commands: MATCH, CREATE, and MERGE. These commands are fundamental to querying and manipulating graph data using Cypher, Neo4j's query language.

Key Concepts

• Cypher: The query language for Neo4j.
• Graph Database: A database that uses graph structures to represent and store data.
• Nodes and Relationships: The core components of graph databases.

MATCH

The MATCH clause is used to find nodes and relationships in the graph.

MATCH (n:Person {name: "Alice"})
RETURN n
            

This query retrieves the node representing a person named Alice.

CREATE

The CREATE clause is used to create new nodes and relationships.

CREATE (n:Person {name: "Bob"})
RETURN n
            

This command creates a new node for a person named Bob.

MERGE

The MERGE clause is a combination of MATCH and CREATE. It ensures that a pattern exists in the graph, creating it if it does not.

MERGE (n:Person {name: "Alice"})
RETURN n
            

If a node with the name Alice exists, it is returned; otherwise, it is created.

Best Practices

• Use MATCH for read operations to avoid unintended data modifications.
• Use CREATE when you need to add new elements.
• Use MERGE to prevent duplicates and ensure unique nodes or relationships.

FAQ