C#

Can you explain the concept of a package in programming and how it is used?

Junior — Middle

OZON

What is the difference between HashSet and List?

Senior

СБЕР

Can you explain what a table join operation in SQL means?

How is data type conversion performed from one type to another in programming?

Is it possible to declare a variable inside an interface?

Junior — Middle

Aston

Do you have practical experience in testing software products?

What does the response status code 500 mean in the HTTP protocol?

How does ConcurrentDictionary work?

Middle+

Pyrus

Задача 2 Запрос выполниться? select field1 from TABLE1 group by field1, field2

Do you plan to implement an asynchronous function for performing calculations?

Review: application code The class contains logic for processing new orders. It retrieves orders and items from the database, then makes an HTTP call to an external Stock microservice, which reserves goods for the order items. If all reservations are successful, the microservice confirms the reservation in Stock and marks the order as processed. The microservice runs in multiple instances, so the Process method can execute in parallel. To prevent processing the same rows, a pessimistic locking mechanism PostgreSQL Select for update ... skip locked is used. The IBus implementation sends messages to RabbitMq. ```csharp public sealed class PendingOrdersProcessor { public async Task PendingOrdersProcessor(ILogger logger, IBus bus, HttpStockService st { var env = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT"); var cs = _cs[env]; _db = new OrdersRepository(cs); _bus = bus; logger = logger; ``` ```csharp _stockService = stockService; } private readonly ILogger _logger; private readonly IOrdersRepository _db; private readonly IStockService _stockService; private readonly IBus _bus; private static readonly Dictionary<string, string> _cs = new { { "Development", "User ID=root;Password=myPassword;Host=localhost;Port=5432;Database=myDataBase" }, { "Production", "User ID=root;Password=myPassword;Host=prod-db;Port=5432;Database= "Pooling=true;Min Pool Size=0;Max Pool Size=1;" } }; ```

Is it possible to make DbContext (EF Core) a Singleton? What are the advantages and disadvantages?

Is it possible to terminate the lifecycle of a Scoped object before the completion of the HTTP request processing?

Can you explain what inheritance means in object-oriented programming?

Explain the LIKE function in SQL and how it is used for data searching.

What will be the order of output in the code: setTimeout(() => alert("timeout")); Promise.resolve().then(() => alert("promise")); alert("code");? What is this mechanism called?

Have you had practical experience in setting up and working with relationships between tables in a database?

What lifetimes exist in .NET DI and why should Redis ConnectionMultiplexer be registered as a Singleton?

Middle

Альфа-Банк

What is the purpose of overriding the GetHashCode method in an object?

What are the differences between the keywords const and readonly in C#?