What role does the external schema play in the three-schema approach?

What role does the external schema play in the three-schema approach?

• A. Represents the stored data structure
• B. Serves as a model for the entire enterprise
• C. Provides a user-specific view of subsets of the enterprise model
• D. Handles operations on complex queries

Answer: (C)

The external schema plays a crucial role in the three-schema approach by providing a user-specific view of subsets of the enterprise model. This means it allows different users or user applications to interact with the data in a way that is tailored to their needs, without having to understand the underlying complexities of the entire database system. The external schema can present data in a format that is more understandable or relevant for specific user groups, making it easier to access and manipulate the data they require. By creating these tailored views, the external schema helps ensure that users can work with data efficiently, leveraging only the relevant information pertinent to their tasks while abstracting away the details of the internal schema and the overall data structure. This not only facilitates usability but also enhances security by ensuring that users only have access to data that they are authorized to view.

The external schema plays a crucial role in the three-schema approach by providing a user-specific view of subsets of the enterprise model. This means it allows different users or user applications to interact with the data in a way that is tailored to their needs, without having to understand the underlying complexities of the entire database system. The external schema can present data in a format that is more understandable or relevant for specific user groups, making it easier to access and manipulate the data they require.

By creating these tailored views, the external schema helps ensure that users can work with data efficiently, leveraging only the relevant information pertinent to their tasks while abstracting away the details of the internal schema and the overall data structure. This not only facilitates usability but also enhances security by ensuring that users only have access to data that they are authorized to view.