What are the differences between relational and non-relational databases in cloud storage?

Relational databases organize data using table structures, emphasizing ACID (Atomicity, Consistency, Isolation, Durability) properties. They are suitable for structured data and complex transaction processing scenarios, such as financial transactions. Non-relational databases, on the other hand, adopt flexible models (e.g., key-value or document storage), optimize scalability and performance, and are used in big data and real-time analysis scenarios like the Internet of Things. Both provide fundamental support for different data needs in cloud storage.

At their core, relational databases rely on fixed schemas and SQL queries to ensure strong consistency, making them suitable for enterprise applications like inventory management. Non-relational databases encompass various models (column-family, graph databases) and are based on the BASE principles (Basic Availability, Soft State, Eventual Consistency). They support distributed deployment and rapid iteration, driving the elastic growth of cloud-native applications.

In practical applications, relational databases are suitable for high-consistency businesses (e.g., accounting systems) to ensure data accuracy. Non-relational databases facilitate unstructured data processing (e.g., user profiling), reduce latency and costs through horizontal scaling, and enhance business agility, such as in e-commerce recommendation engines.