Data Access Layer
A Data Access Layer (DAL) is a software design pattern that separates the logic for accessing data from the business logic in an application. It provides an abstraction layer between the application and the data source, such as a database, API, or file system, to handle data retrieval, storage, and manipulation. This pattern centralizes data operations, improving maintainability, testability, and reducing code duplication.
Developers should implement a Data Access Layer when building applications that require complex data interactions, such as web apps, enterprise systems, or services with multiple data sources. It is crucial for scenarios involving database migrations, switching data storage technologies, or enforcing data consistency and security policies. By isolating data access code, it simplifies unit testing, enhances scalability, and adheres to the separation of concerns principle.