NoSQL With Spring Boot

What is NoSQL?

NoSQL refers to a category of database management systems that differ from traditional relational databases like MySQL, PostgreSQL, or Oracle. NoSQL databases are designed to handle large volumes of data and are particularly suited for applications that require scalability, flexibility, and high performance. They are often used in scenarios where the data is unstructured, semi-structured, or where the schema may change over time.

Key Characteristics of NoSQL Databases

• Schema-less: Unlike relational databases, NoSQL databases do not require a fixed schema, making them flexible and able to handle varying data structures.
• Scalability: NoSQL databases are designed to scale horizontally, meaning you can add more servers to handle increased load, making them ideal for big data applications.
• Distributed: Most NoSQL databases are designed to run on distributed clusters, ensuring high availability and fault tolerance.
• Types of NoSQL Databases:
  • Document-based: Stores data as documents, usually in JSON or BSON format (e.g., MongoDB).
  • Key-Value: Stores data as key-value pairs (e.g., Redis, DynamoDB).
  • Column-family: Stores data in columns rather than rows, optimized for read and write performance (e.g., Apache Cassandra, HBase).
  • Graph: Stores data in graph structures, representing relationships between data points (e.g., Neo4j).

Integrating Cassandra with Spring Boot

Apache Cassandra is a highly scalable, distributed NoSQL database designed for handling large amounts of data across many commodity servers, with no single point of failure. Integrating Cassandra with Spring Boot allows you to leverage the powerful data handling capabilities of Cassandra while using the familiar Spring framework for application development.

Here’s a step-by-step guide to integrating Cassandra with Spring Boot:

Add Dependencies

• First, you need to add the necessary dependencies to your pom.xml (for Maven) or build.gradle (for Gradle) file.

<!-- Maven Dependency -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-cassandra</artifactId>
</dependency>

// Gradle Dependency
implementation 'org.springframework.boot:spring-boot-starter-data-cassandra'

Configure Cassandra Properties

In your application.properties or application.yml, configure the necessary properties to connect to your Cassandra database.

spring.data.cassandra.contact-points=127.0.0.1
spring.data.cassandra.port=9042
spring.data.cassandra.keyspace-name=your_keyspace_name
spring.data.cassandra.username=cassandra_username
spring.data.cassandra.password=cassandra_password

Alternatively, you can use application.yml:

spring:
  data:
    cassandra:
      contact-points: 127.0.0.1
      port: 9042
      keyspace-name: your_keyspace_name
      username: cassandra_username
      password: cassandra_password

Define Cassandra Entity

Define an entity class that maps to a table in Cassandra. Annotate it with @Table and define the fields with @PrimaryKey and @Column.

import org.springframework.data.cassandra.core.mapping.PrimaryKey;
import org.springframework.data.cassandra.core.mapping.Table;

@Table
public class LearnSpringBootOnlineEntity {

    @PrimaryKey
    private String id;

    @Column("column_name")
    private String fieldName;

    // Getters and setters
}

Create a Repository Interface

Create a repository interface that extends CassandraRepository to perform CRUD operations on your Cassandra table.

import org.springframework.data.cassandra.repository.CassandraRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface LearnSpringBootOnlineRepository extends CassandraRepository<LearnSpringBootOnlineEntity, String> {
}

Use the Repository in Your Service

Inject the repository into your service class and use it to perform database operations.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class LearnSpringBootOnlineEntityService {

    @Autowired
    private LearnSpringBootOnlineRepository repository;

    public LearnSpringBootOnlineEntity save(LearnSpringBootOnlineEntity entity) {
        return repository.save(entity);
    }

    public List<LearnSpringBootOnlineEntity> findAll() {
        return repository.findAll();
    }
}

Run Your Application

Start your Spring Boot application. It should connect to the Cassandra database and allow you to perform operations using the repository.

Example Application Flow

Create Keyspace and Table in Cassandra:

CREATE KEYSPACE your_keyspace_name WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 1};

CREATE TABLE your_keyspace_name.learn_spring_boot_online_entity(
    id UUID PRIMARY KEY,
    field_name text
);

Run the Spring Boot Application

Use @RestController to expose endpoints that interact with the Cassandra database.

Test CRUD Operations

Use Postman or cURL to interact with the REST API and verify that the data is being saved and retrieved correctly from Cassandra.

Conclusion

Integrating Cassandra with Spring Boot offers a robust solution for building scalable, high-performance applications that can handle large volumes of data. By following the steps outlined—adding the necessary dependencies, configuring Cassandra properties, defining entity and repository classes, and using @RestController to create endpoints—you can seamlessly connect your Spring Boot application with a distributed NoSQL database like Cassandra. This integration empowers developers to harness the flexibility and scalability of Cassandra while benefiting from the productivity and ease of use provided by the Spring framework.