Why is an API required between the database and the client application?

API (Application Programming Interface) acts as an intermediary between the database and the client application, providing a standardized way of interaction.

The main reasons for its necessity:

• Encapsulation: Hides the complexity of the internal database structure, providing a clear set of functions (methods) for working with data (CRUD - Create, Read, Update, Delete). The client application does not need to know specifics about how data is stored.
• Security: API controls access to the database and defines which operations are allowed. This prevents direct access to data and potential vulnerabilities.
• Scalability: API allows serving multiple clients simultaneously and scaling the storage and processing system independently of client applications.
• Separation of Concerns: Data access logic and business logic are separated from the presentation layer (client application). This simplifies maintenance and development.
• Flexibility: Allows changing the database structure or the used DBMS without the need to modify the client application, as long as the API remains unchanged.
• Diversity of clients: One API can serve different types of clients (web, mobile applications, desktop programs) using standardized protocols (e.g., HTTP/REST).

Without API, the client application would have to execute SQL queries directly, which would be unsafe, difficult to manage, inflexible, and would complicate support.