How do you implement Cassandra CQL queries in Spring Boot?

Table of Contents

• Introduction
• Using CassandraTemplate for Custom CQL Queries
  • 1. Selecting Data with CQL
    • Example: Selecting Users by Name
  • 2. Inserting Data with CQL
    • Example: Inserting a New User
  • 3. Updating Data with CQL
    • Example: Updating User Email
  • 4. Deleting Data with CQL
    • Example: Deleting a User by ID
• Using CassandraRepository with Custom Queries
  • 1. Defining Custom Query Methods in Repository
    • Example: Custom Query to Find Users by Email
  • 2. Using @Query for Insert or Update Operations
    • Example: Custom Query for Batch Insert
• Conclusion

Introduction

Cassandra Query Language (CQL) is the language used to interact with Cassandra databases, similar to SQL. In a Spring Boot application, you can implement CQL queries using CassandraTemplate for custom queries or CassandraRepository for predefined methods. This guide explains how to perform custom CQL queries in Spring Boot using both approaches, demonstrating how to execute select, insert, update, and delete operations using CQL.

Using CassandraTemplate for Custom CQL Queries

1. Selecting Data with CQL

With CassandraTemplate, you can execute custom CQL queries directly using the select method.

Example: Selecting Users by Name

In this example:

• The select method executes a custom query to fetch all users with the given name.
• You use Query.query to build the CQL query with a condition.

2. Inserting Data with CQL

You can insert data using CQL by using the insert method in CassandraTemplate.

Example: Inserting a New User

In this example:

• The insert method inserts a new user into the database using CQL.

3. Updating Data with CQL

To update data using custom CQL queries, you can use the update method in CassandraTemplate.

Example: Updating User Email

In this example:

• The update method updates the email of the user with the specified userId.

4. Deleting Data with CQL

You can delete data using custom CQL queries with the delete method in CassandraTemplate.

Example: Deleting a User by ID

In this example:

• The delete method removes the user from the database using a CQL query.

Using CassandraRepository with Custom Queries

In addition to CassandraTemplate, CassandraRepository allows you to define custom query methods using CQL syntax in Spring Data Cassandra.

1. Defining Custom Query Methods in Repository

You can define custom queries in the repository interface using @Query annotation to specify the CQL query.

Example: Custom Query to Find Users by Email

In this example:

• The @Query annotation defines a custom CQL query to fetch users by their email address.

2. Using @Query for Insert or Update Operations

While CassandraRepository generally uses the save method for insert and update operations, you can also define custom CQL queries for more complex scenarios.

Example: Custom Query for Batch Insert

In this example:

• The @Query annotation is used to execute a custom batch insert CQL query.

Conclusion

Implementing Cassandra CQL queries in Spring Boot can be achieved using either CassandraTemplate or CassandraRepository. CassandraTemplate provides a more flexible and programmatically-driven approach for executing custom queries, while CassandraRepository leverages the power of Spring Data to simplify basic query operations. Both approaches enable you to easily integrate and work with Cassandra in Spring Boot, whether you are using simple queries or more complex CQL commands.