Create Index

In Neo4j, an index is used to speed up the search for nodes or relationships in a graph. Creating an index in Neo4j is easy and can greatly improve search performance.

Syntax

The syntax for creating an index in Neo4j is as follows:

CREATE [UNIQUE] INDEX index_name FOR (n:label_name) ON (n.property_name)

• index_name is the name of the index to be created. This is user-defined.
• UNIQUE is an optional keyword that is used to create a unique index, which ensures that no two nodes have the same value for the indexed property.
• label_name is the name of the label that the nodes should have to be included in the index.
• property_name is the name of the property that should be indexed.

Example

For example, let's say we have a graph that contains a Person label, and we want to create an index on the name property of nodes that have this label. The following Cypher query would create the index:

CREATE INDEX ON :Person(name)

Output

If the index creation is successful, Neo4j will return a message confirming the index creation.

> Added 1 index, took 123ms.

Explanation

In the example above, we create an index named index_name on the name property of nodes that have the Person label. The use of UNIQUE keyword makes the index unique, which ensures that no two nodes have the same value for the indexed property. This means that we can quickly search for Person nodes based on their name property.

Use

Indexes are used to improve the speed of search queries in Neo4j. They allow for faster search times by creating a sort of "map" that allows you to locate nodes based on their indexed properties quickly.

Important Points

• Creating an index in Neo4j can greatly improve search performance.
• Indexes can be created on properties of a specific label.
• Use of UNIQUE keyword allows you to create a unique index that enforces uniqueness among all indexed nodes.
• It is important not to create too many indexes, as too many indexes can degrade the performance of write operations.

Summary

Creating an index in Neo4j is a straightforward process. Indexes can be created on properties of a specific label, and they improve the speed of search queries by creating a "map" that allows for faster search times. The use of the UNIQUE keyword allows you to create a unique index, and it is important to not create too many indexes, as too many indexes can degrade write operation performance.