Data Access Layer

What is the primary purpose of the Data Access Layer in a software architecture?. To handle business rules and domain validations. To provide a clean, consistent, and secure way to access data sources. To send HTTP responses to the client.

“The DAL is responsible for deciding what data the application needs according to business rules.”. True. False.

Which of the following best describes the DAL’s role in the architecture?. It is the layer that transforms user interfaces into service requests. It is the layer that encapsulates storage logic so the rest of the system remains database-agnostic. It is the layer that runs domain workflows based on business rules.

“One of the goals of the DAL is to prevent SQL injection by using safe querying mechanisms.”. True. False.

What does the Data Access Layer abstract from the rest of the application?. The syntax and mechanics of queries to the data source. The routing rules for handling HTTP requests. The business logic validations.

Which description reflects the core definition of the Data Access Layer?. A layer designed to centralize all database operations, allowing the application to remain independent of data storage details. A layer that manages HTTP headers, cookies, and client sessions. A layer that orchestrates complex domain logic and workflows.

“The DAL exists mainly to isolate data access logic and avoid spreading SQL/queries across the application.”. True. False.

Which of the following is a core responsibility of the Data Access Layer?. Managing user authentication and authorization. Executing CRUD operations (Create, Read, Update, Delete). Handling UI rendering and input formatting.

“The DAL is responsible for managing database connections and closing them properly.”. True. False.

Which of the following is NOT a responsibility of the DAL?. Transforming raw database rows into domain objects. Deciding business validation rules. Executing parameterized queries to ensure safety.

What responsibility does the DAL have related to query execution?. Applying business-level decision-making before running queries. Ensuring queries are performed efficiently and securely. Sending formatted JSON responses to the client.

The DAL is responsible for implementing transaction management such as commit, rollback, and atomic operations. True. False.

Which of the following best describes DAL responsibility for data mapping?. Mapping HTTP requests into controller-friendly objects. Mapping database records to entities or DTOs. Mapping user interface components to backend routes.

Which of the following responsibilities helps other layers stay database-agnostic?. The DAL hides SQL queries and exposes only high-level operations. The DAL generates HTML pages based on templates. The DAL defines business processing workflows.

Which component is commonly responsible for encapsulating all database operations for a specific entity?. Controller. Repository. Serializer.

“A DAO (Data Access Object) is a component that isolates low-level database interactions.”. True. False.

Which component is responsible for converting database results into application objects?. Data Mapper. Router. Validator.

“Entities in the DAL represent business logic behavior.”. True. False.

What is the primary role of the ORM component in the DAL?. Handle HTTP routing. Manage object-to-database mapping. Execute business logic workflows.

Which DAL component manages connections, pooling, and communication with the database driver?. Connection Manager. Repository. Controller.

“Query Builders are used in the DAL to generate SQL dynamically without writing raw queries.”. True. False.

Which component handles grouping related persistence operations to ensure atomicity?. Template Engine. Unit of Work. Mapper.

Which component represents the actual database schema as objects in the DAL. Entities / Models. Controllers. Services.

“The DAL may also include caching components to reduce repeated queries.”. True. False.

Where does the Data Access Layer typically sit within a traditional layered architecture?. Above the Presentation Layer. Below the Service/Business Layer. At the same level as Controllers.

“The Data Access Layer should be isolated so that higher layers never interact directly with the database.”. True. False.

What is the main benefit of placing the DAL below the Service Layer?. It allows the Service Layer to modify the database schema directly. It allows the Service Layer to remain independent of database technology. It forces the Service Layer to write SQL queries.

“The DAL can communicate directly with external APIs in addition to databases.”. True. False.

Which interaction path correctly reflects the direction of communication in a layered architecture?. Presentation → Data Access → Service → Database. Service → Presentation → Data Access → Database. Presentation → Service → Data Access → Database.

What architectural role does the DAL fulfill when sitting between business logic and data sources?. It acts as a translator and protector of data operations. It acts as an orchestrator of HTTP session state. It acts as a controller for user input.

“A well-designed DAL allows changes in the database engine (e.g., from MySQL to PostgreSQL) without affecting service or presentation layers.”. True. False.

Which statement best describes a Data Model?. It represents business rules and domain behaviors. It represents how data is structured and stored in the database. It represents UI components and how data is displayed to the user.

“Domain Models contain business logic and enforce invariants, while Data Models do not.”. True. False.

Which of the following happens when a Domain Model is tightly coupled to a Data Model?. Business logic becomes database-agnostic and easier to test. Business logic becomes dependent on database structures and harder to maintain. Controllers automatically generate SQL queries.

What is a common technique to avoid mixing Data Models with Domain Models?. Use the same class for both storage and domain logic. Introduce mappers or translators between Data Models and Domain Models. Allow controllers to directly modify Data Models.

“In complex systems, Domain Models may contain rich behavior, while Data Models remain simple representations of storage.”. True. False.