Top 57 Entity Framework Interview Questions And Answers

Question 1

What are the _benefits_ of using EF?

Accepted Answer

The main and the only benefit of EF is it auto-generates code for the Model (middle layer), Data Access Layer, and mapping code, thus reducing a lot of development time.

Question 2

What is Entity Framework?

Accepted Answer

ADO.NET EF is an ORM (object-relational mapping) which creates a higher abstract object model over ADO.NET components. So rather than getting into dataset, datatables, command, and connection objects as shown in the below code, you work on higher level domain objects like customers, suppliers, etc.

Question 3

Mention in what all scenarios Entity Framework can be applicable?

Accepted Answer

Entity Framework can be applicable in three scenarios

* If you have an existing database already or you want to build your database first than other parts of the application
* If your prime focus is your domain classes and then create the database from your domain classes
* If you want to design your database schema on the visual designer and create the classes and database

Question 4

What is _migration_ in Entity Framework?

Accepted Answer

Entity Framework introduced a migration tool that automatically updates the database schema when your model changes without losing any existing data or other database objects.

There are two kinds of Migration:

* Automated Migration
* Code-based Migration

Question 5

What is the purpose of a `DBContext` class?

Accepted Answer

You can think of `DbContext` as the database connection and a set of tables, and `DbSet` as a representation of the tables themselves. The `DbContext` allows you to link your model properties (presumably using the Entity Framework) to your database with a connection string.

Later, when you wish to refer to a database in your controller to handle data, you reference the `DbContext`.

Question 6

What is _Mapping_?

Accepted Answer

The Mapping will have the information on how the Conceptual Models are mapped to Storage Models.

Question 7

What are `scalar` and `navigation` properties in Entity Framework?

Accepted Answer

* _Scalar properties_ are those where actual values are contained in the entities. Normally a scalar property will map to a database field.
* _Navigation properties_ help to navigate from one entity to another entity directly in the code.

Question 8

Mention what is _Code First Approach_ and _Model First Approach_ in Entity Framework?

Accepted Answer

In Entity Framework,

*   **Model First Approach:** In this approach we create entities, relationships directly on the design surface of EDMX.
*   **Code Approach:** For code approach we avoid working with the visual designer or entity framework.

Question 9

What is _Code First_ approach in Entity Framework?

Accepted Answer

In **Code First** approach we avoid working with the Visual Designer of Entity Framework. In other words the EDMX file is excluded from the solution. So you now have complete control over the context class as well as the entity classes.

Question 10

What is _Conceptual Model_?

Accepted Answer

**Conceptual Models** are the model classes which contain the relationships. These are independent of the database design.

Top 57 Entity Framework Interview Questions

What is Entity Framework?

What are the benefits of using EF?

Mention in what all scenarios Entity Framework can be applicable?

What is pluralize and singularize in the Entity Framework?

Mention what is Code First Approach and Model First Approach in Entity Framework?

What is Code First approach in Entity Framework?

What is the purpose of a DBContext class?

What is Conceptual Model?

What is migration in Entity Framework?

What is Mapping?

What is Storage Model?

What are scalar and navigation properties in Entity Framework?

What are complex types in Entity Framework?

Could you explain the difference between Optimistic vs Pessimistic locking?

What is the importance of EDMX file in Entity Framework?

What are POCO classes in Entity Framework?

What are the different approaches supported in the Entity Framework to create Entity Model?

Can you explain Lazy Loading in a detailed manner?

What is EF Data Access Architecture?

What are the advantages and disadvantages of Database First Approach?

What are the components of Entity Framework Architecture?

What are the advantages of Model First Approach?

Explain how you can load related entities in EF?

What is Eager Loading?

What is the role of Entity Client Data Provider?

How can we handle concurrency in Entity Framework?

Explain Lazy Loading, Eager Loading, and Explicit Loading?

What are the advantages/disadvantages of Code First Approach?

What is Optimistic Locking?

What’s the difference between LINQ to SQL and Entity Framework?

What are the disadvantages of using static DbContext?

Which type of loading is good in which scenario?

When would you use EF6 vs EF Core?

Name some differences between Express vs Recoverable messages

Is DbContext thread safe?

Why shouldn't I use the Repository Pattern with Entity Framework?

What are T4 templates?

What is relationship between Repository and Unit of Work?

Could you explain Pessimistic locking?

Can you explain CSDL, SSDL and MSL sections in an EDMX file?

What types of system generated messages do you know?

How can you enhance the performance of Entity Framework?

What is faster - ADO.NET or ADO.NET Entity Framework?

What is the difference between POCO, Code First, and simple EF approach?

What is the difference between ObjectContext and DbContext?

What is the difference between Code First, Model First and Database First?

What difference does .AsNoTracking() make?

What are the advantages and disadvantages of creating a Global Entities Context for the application (i.e. one static instance)?

What is client wins and store wins mode in Entity Framework concurrency?

What is the difference between Automatic Migration vs Code-base Migration?

When would you use SaveChanges(false) + AcceptAllChanges()?

What's the difference between .SaveChanges() and .AcceptAllChanges()?

Can I use Entity Framework 6 in .Net Core?

How can we do pessimistic locking in Entity Framework?

What are the different ways of creating these domain/entity objects?

How do I delete multiple rows in Entity Framework (without foreach)?

How do I view the SQL generated by the Entity Framework?

What is `pluralize` and `singularize` in the Entity Framework?

What is the purpose of a `DBContext` class?

What are `scalar` and `navigation` properties in Entity Framework?

Explain `Lazy Loading`, `Eager Loading`, and `Explicit Loading`?

What are the disadvantages of using `static` DbContext?

Name some differences between `Express` vs `Recoverable` messages

Is `DbContext` thread safe?

What are `T4` templates?

Can you explain `CSDL`, `SSDL` and `MSL` sections in an EDMX file?

What is the difference between `ObjectContext` and `DbContext`?

What difference does `.AsNoTracking()` make?

What are the advantages and disadvantages of creating a Global Entities Context for the application (i.e. one `static` instance)?

When would you use `SaveChanges(false)` + `AcceptAllChanges()`?

What's the difference between `.SaveChanges()` and `.AcceptAllChanges()`?

How do I delete multiple rows in Entity Framework (without `foreach`)?