Spring Boot Backend Development Course, What is NoSQL

In recent years, the paradigm of software development has changed significantly. Especially with the explosive increase in the amount of data, new methods of database management have become necessary. While traditional relational databases are still widely used, NoSQL databases are emerging, creating a new trend. In this article, we will explain in detail what NoSQL is in Spring Boot backend development, when it should be used, and the types and characteristics of NoSQL databases.

Concept of NoSQL

NoSQL stands for “Not Only SQL,” referring to a data storage model developed as an alternative to traditional relational database management systems (RDBMS). NoSQL supports various data models, providing the capability to flexibly store and query large amounts of unstructured or semi-structured data that relational databases find difficult to handle.

The main features of NoSQL are as follows:

• Schema Flexibility: NoSQL databases do not have a fixed schema, allowing for easy adaptation even if the data structure changes.
• Horizontal Scalability: As the volume of data increases, servers can be added to the cluster to scale horizontally.
• High Availability: To maintain high availability even when failures occur, replication and distributed storage capabilities are provided.

The Need for NoSQL

The reasons for the need for NoSQL are primarily as follows.

• Handling Large Amounts of Data: It is useful when large-scale data collection and storage are needed, such as IoT, social media, and log data.
• Unstructured Data: While relational databases are optimized for structured data, NoSQL is suitable when it is necessary to store images, videos, and data in various formats.
• Fast Development: It allows for quick adaptation to dynamic data structures, improving the speed of application development.

Types of NoSQL Databases

NoSQL databases can be classified into various types, each of which is suitable for specific use cases based on its characteristics.

1. Key-Value Store

A key-value store is a structure where data is stored as key-value pairs. It offers a simple structure and fast query speed, making it suitable for session management, caching, and simple data storage. Examples include Redis and DynamoDB.

2. Document Store

A document store saves data in document formats such as JSON, BSON, and XML. The schema for the data is flexible, allowing other structured data to be stored within the same document. MongoDB and CouchDB are representative examples.

3. Column-Family Store

A column-family store is optimized for handling large volumes of data by storing data in column units. By keeping frequently used columns in memory, performance can be improved. Apache Cassandra and HBase are typical examples.

4. Graph Database

A graph database stores data represented as nodes and edges. It is suitable for data models where relationships are significant and is commonly used in social network analysis. Neo4j is well known in this category.

Integration of Spring Boot and NoSQL

Spring Boot supports various Spring Data projects for integration with NoSQL databases. In this section, we will look at a simple integration example with MongoDB using Spring Boot.

1. Adding Dependencies

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
    

2. MongoDB Configuration

Add the connection settings for MongoDB in the application.properties file.

        spring.data.mongodb.uri=mongodb://localhost:27017/testdb
    

3. Creating Domain Class

    import org.springframework.data.annotation.Id;
    import org.springframework.data.mongodb.core.mapping.Document;

    @Document(collection = "user")
    public class User {
        @Id
        private String id;
        private String name;
        private String email;

        // getters and setters
    }
    

4. Creating Repository

    import org.springframework.data.mongodb.repository.MongoRepository;

    public interface UserRepository extends MongoRepository<User, String> {
        User findByName(String name);
    }
    

5. Creating Service and Controller

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

    import java.util.List;

    @Service
    public class UserService {
        @Autowired
        private UserRepository userRepository;

        public List<User> getAllUsers() {
            return userRepository.findAll();
        }

        public User getUserByName(String name) {
            return userRepository.findByName(name);
        }
        
        public void createUser(User user) {
            userRepository.save(user);
        }
    }
    

Conclusion

NoSQL databases play an important role in modern web applications, helping developers meet various data processing requirements. By using them with Spring Boot, they offer higher productivity and flexibility, especially demonstrating their value in unstructured data environments. Through this course, I hope to summarize the essence of NoSQL and its practical use cases in Spring Boot.