Entity Framework Interview Questions and Answers for Freshers

Entity Framework interview questions and answers for freshers can be helpful. Here’s a selection:

Q1. What is Entity Framework (EF)?

Ans: Entity Framework is an ORM framework for .NET applications that enables developers to work with relational data using domain-specific objects.

Q2. What are the key components of Entity Framework?

Ans: Components include Entity Data Model (EDM), DbContext, DbSet, LINQ to Entities, and Entity SQL.

Q3. Explain the different approaches in Entity Framework.

Ans: Code First, Database First, and Model First. Each approach emphasizes different aspects of database development from code-centric to database design-centric.

Q4. What is DbContext in Entity Framework?

Ans: DbContext is a primary class that acts as a bridge between the domain or entity classes and the database. It manages database connections and operations.

Q5. How does Lazy Loading work in Entity Framework?

Ans: Lazy Loading defers loading related entities until they are accessed. It helps optimize performance by loading data only when needed.

Q6. What is the purpose of DbSet in Entity Framework?

Ans: DbSet represents a collection of entities of a specific type (e.g., DbSet<Product>) in the context. It is used for querying and performing CRUD operations.

Q7. Explain Code First approach in Entity Framework.

Ans: Code First allows developers to define domain classes first and then generate a database schema from those classes. Configuration is done through conventions or Fluent API.

Q8. What is the EDMX file in Entity Framework?

Ans: EDMX (Entity Data Model XML) file visually represents the Entity Data Model. It includes conceptual, storage, and mapping details.

Q9. How does Entity Framework handle relationships between entities?

Ans: Relationships are defined using navigation properties (e.g., navigation collections or references). EF supports one-to-one, one-to-many, and many-to-many relationships.

Q10. What is migration in Entity Framework?

Ans: Migration is the process of updating a database schema to reflect changes in the application’s model. It helps keep the database schema synchronized with code changes.

Q11. What is Fluent API in Entity Framework?

Ans: Fluent API is an advanced way to configure model classes and relationships in Entity Framework using method chaining and configuration classes.

Q12. How can you optimize performance in Entity Framework?

Ans: Techniques include avoiding unnecessary lazy loading, using stored procedures for complex queries, optimizing LINQ queries, and indexing database tables.

Q13. Explain Database First approach in Entity Framework.

Ans: Database First starts with an existing database schema and generates entity classes and DbContext based on that schema using EDMX or scaffolding.

Q14. What are complex types in Entity Framework?

Ans: Complex types are non-scalar properties that contain multiple scalar properties. They help organize related properties within entities but cannot participate in relationships.

Q15. How does Entity Framework prevent SQL injection?

Ans: EF prevents SQL injection by parameterizing queries generated from LINQ statements, ensuring that user inputs are treated as parameters rather than concatenated into SQL strings.

Q16. What is the difference between Add and AddRange methods in Entity Framework?

Ans: Add adds a single entity to a DbSet, while AddRange adds multiple entities. AddRange is more efficient when inserting multiple records at once.

Q17. Explain eager loading and lazy loading in Entity Framework.

Ans: Eager loading loads related entities along with the main entity in a single query using Include method, whereas lazy loading defers loading related entities until they are accessed.

Q18. What are the benefits of using Entity Framework over ADO.NET?

Ans: EF simplifies data access by eliminating the need for manual mapping between objects and database tables, supports LINQ for querying, and handles database operations automatically.

Q19. How does Entity Framework handle transactions?

Ans: EF supports transactions using DbContext.Database.BeginTransaction method, allowing developers to manage atomicity and consistency across multiple database operations.

Q20. What are the limitations of Entity Framework?

Ans: Limitations include performance overhead compared to ADO.NET in certain scenarios, complexity in managing large models, and lack of support for some advanced database features.

21. What is TPH (Table per Hierarchy) in Entity Framework?

Ans: TPH is an inheritance mapping strategy where all types in an inheritance hierarchy are mapped to a single database table, distinguished by a discriminator column.

Q22. How does Entity Framework ensure database independence?

Ans: EF ensures database independence through provider model architecture, where database-specific providers (e.g., SQL Server, MySQL) implement common interfaces to interact with the database.

Q23. What is the role of the Entity Data Model (EDM) in Entity Framework?

Ans: EDM defines the conceptual model of data as entities and relationships, abstracting the database schema and providing a conceptual view of data used by EF.

Q24. Explain the process of querying data using LINQ in Entity Framework.

Ans: LINQ queries in EF are written against DbSet properties of DbContext, translated into SQL queries, executed against the database, and materialized into objects.

Q25. How can you ensure data consistency in Entity Framework?

Ans: Data consistency is ensured by maintaining transactional integrity, validating data before saving changes, and handling concurrency issues using optimistic or pessimistic concurrency control.

Summary

These questions and answers provide a solid foundation for preparing for Entity Framework interviews, covering key concepts and practical aspects. Read more: Online Interview Questions