MCSD Entity Framework and Data Access 1

Question 1

What is Entity Framework (EF) in the context of .NET development?

Accepted Answer

An ORM that maps .NET objects to database tables

Answer

Entity Framework is an ORM (Object-Relational Mapper) that allows .NET developers to work with databases using objects.

Question 2

In Entity Framework Code-First, what triggers a database schema migration?

Accepted Answer

Running `Add-Migration` after modifying the model classes

Answer

Running `Add-Migration` in the Package Manager Console generates a migration script based on model class changes.

Question 3

What does `DbContext` represent in Entity Framework?

Accepted Answer

The session with the database, exposing DbSet properties for querying

Answer

`DbContext` is the primary class in Entity Framework that manages the database connection and entity change tracking.

Question 4

Which Entity Framework loading strategy fetches related entities in separate queries on demand?

Accepted Answer

Lazy loading

Answer

Lazy loading defers loading of related entities until they are accessed, issuing additional queries at that point.

Question 5

What does the `[Key]` data annotation do in Entity Framework Code-First?

Accepted Answer

Designates the property as the primary key of the entity

Answer

The `[Key]` attribute marks a property as the primary key, used when EF cannot infer it by convention.

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