Entity Framework вопросы и ответы для интервью

Вопрос 21. Explain the purpose of the [Key] attribute in Entity Framework.

The [Key] attribute is used to specify the primary key property of an entity when it does not match the default convention.

Example:

[Key] public int MyCustomId { get; set; }

Вопрос 22. What is the purpose of the [ConcurrencyCheck] attribute in Entity Framework?

The [ConcurrencyCheck] attribute is used to specify that a property should be included in the WHERE clause of an UPDATE or DELETE statement to check for concurrency conflicts.

Example:

[ConcurrencyCheck] public byte[] RowVersion { get; set; }

Вопрос 23. Explain the purpose of the [NotMapped] attribute in Entity Framework.

The [NotMapped] attribute is used to specify that a property should not be mapped to a column in the database.

Example:

[NotMapped] public string CalculatedProperty { get { /* calculation logic */ } }

Вопрос 24. What is the purpose of the DbSet.Find method in Entity Framework?

The DbSet.Find method is used to retrieve an entity from the database by its primary key value.

Example:

var entity = context.MyEntities.Find(1);

Вопрос 25. Explain the purpose of the IDbSet interface in Entity Framework.

The IDbSet interface is an interface that represents a collection of entities in the context. It is implemented by DbSet.