ASP.NET Core Entity Framework Core 2

Question 1

What does AsNoTracking() do in an EF Core LINQ query?

Accepted Answer

Returns entities without adding them to the change tracker, improving read performance

Answer

AsNoTracking() skips the overhead of the change tracker for read-only scenarios, reducing memory and CPU usage.

Question 2

Which EF Core method applies pending migrations to the database?

Accepted Answer

dotnet ef database update

Answer

dotnet ef database update applies all pending migrations, creating or altering tables as defined in the migration files.

Question 3

What is the purpose of the Fluent API in Entity Framework Core?

Accepted Answer

To configure entity mappings and relationships in OnModelCreating using method chaining

Answer

The Fluent API in OnModelCreating() allows detailed configuration of columns, keys, indexes, and relationships beyond data annotations.

Question 4

Which EF Core loading strategy fetches related entities in the same query using a JOIN?

Accepted Answer

Eager loading with Include()

Answer

Eager loading via Include() fetches related entities in a single SQL query using JOINs, avoiding the N+1 query problem.

Question 5

What does the [Key] attribute do on an entity property in EF Core?

Accepted Answer

Designates the property as the primary key for the entity

Answer

[Key] overrides EF Core's convention of using 'Id' or '{TypeName}Id' as the primary key, explicitly designating the property.

ASP.NET Core Practice Test