Entity Framework

Question 1

How to recovery information of the several tables using entity framework

Answer 1

In the class repository of this entity
I can add the instruction
_context.Products.
Include(p => p.ProductType).
Include(p =>p.ProductBrand)
.FirstOrDefaultAsync(p => p.Id == id);

Question 2

What is the difference between an API and Microservices

Answer 2

The difference is the architecture, in the case of the APi in the majority of the cases use a monolithic architecture that means that all the execution it is in a only container or server in the case of the one application that implements the architecture microservices pattern every service is executed in the different place for example in a docker container or in a different server.

Question 3

What is dependency injection DI

Answer 3

In general is send the instance of a class into the constructor of a new class this with the target of minimize the high coupling an procure the low coupling. This injection of dependency is achievement using interfaces instead of concrete classes.

Question 4

What is IoC (inversion of code)

Answer 4

That is a design pattern in which the control flow of a program is inverted. In the case of dotnet core use specialized classes

Question 5

What classes use dotnet core to implement the DI

Answer 5

ServiceCollection: this class contains a list of the declaration of interfaces or concrete class.

ServiceProvider: This class help to implement the services listed in the service collector.

Both classess are in the DependencyInjection package of dotnetcore

Question 6

How add the services in the service collection and what is its lifecycle?

Answer 6

Using the methods AddSingleton same instance for the entire application, AddScope same instance in a request, AddTransient new instance every time that the object is requested or injected.

Question 7

Which is the authentication strategy using the azure services

Answer 7

Single Sign On (SSO)

Question 8

What are the characteristics of the microservices

Answer 8

Componentization via services, Organized around business capacities, products not projects, smart endpoints and dumb pipes, decentralized Governance, decentralized data management, infrastructure automatization, design for failure, evolutionary design

Question 9

Definition of pattern microservices

Answer 9

Every Service is indepent for any other, with this, we are promove the loose coupling instead of tight coupling , the independence of test and deployment and the use of the stack of technology in every service.

Question 10

Characteristic of the componentization

Answer 10

Independent deployment
Well define interface

Question 11

Characteristics of the decentralized governance

Answer 11

Use of the optimal technology for every specific service. We can use the stack of the optimal technology that solve our objective with a different stack of technologies

Question 12

Characteristics of the Infrastructure automatization

Answer 12

Short Deployment cycles
Automatic Testing
Automatic Deployment

Question 13

Characteristics of the design for failure

Answer 13

We would make extensive use of logging and monitoring
In the case of error will be three actions, 1 catch the error, 2 try the connection again, 3 log the error
For this activities exists tools to help us to make this activities automatically like kubernetes.

increase system reliability

Question 14

Recommend attributes in Microservices

Answer 14

*Componentization
*Organized around business capacities
*Decentralized Governance
*Decentralized data
*Infrastructure automatization

Question 15

Issues that microservices solve

Answer 15

*Single Technology Platform
*Inflexible deployment
*Inefficient resources use

Question 16

Components of docker

Answer 16

Containers in which we can configurate the infraestructure, server, framework, etc

Question 17

What is CI/CD

Answer 17

Continuous Integration / Continuous Delivery

Question 18

What are the stages in the process of integration and delivery

Answer 18

The stages for integration are Buld-> Unit Test-> Integration Test
The stages for Delivery are Staging->deployment

Question 19

What use CI/CD

Answer 19

Faster release cycle
Reliability
Reporting

Question 20

What problems solve the containers management

Answer 20

Deployment
Scalability
Monitoring
Routing
High-Avaliability

Question 21

Main Activities that cover Kubernetes

Answer 21

Routing
Scaling
High-Availability
Automated deployment
Configuration Management

Question 22

Which are the parts for the entity data model

Answer 22

Storage Model
Conceptual Model
Mapping

Question 23

What is DataAnnotation

Answer 23

In the properties of the entities we can add metaproperties to add characteristics and functionalities like example when the property is required in the table of the database

Question 24

What is fluent API?

Answer 24

We can add properties directly in the tables using the capacity of the language to use function lambda especially at the class DbContext in the method OnModelCreating

Question 25

How to apply relationships using entityframework

Answer 25

Using Data Annotations or Fluent API

Question 26

What are extension methods

Answer 26

Are the methods that use lambda functions in it’s sintax for example in use of linq

Question 27

How many joins has linq

Answer 27

Three types: Inner Join
Group Join
Cross Join

Question 28

What is lazy loading?

Answer 28

When we use entity framework some entities has a properties of the kind of other entity for example employee has employeRole, then when we recover a entity with the single method like Single the value of the property is queried until that property is used,

Question 29

What is Eager loading?

Answer 29

It is the opposite of lazy loading the entity is loaded with the minus number of queries possible. This is executed add at the middle of the linq query the method Include().

Question 30

What is explicit loading?

Answer 30

It is a load of data from database in an explicit way means its executed immediately after to execute the action. This is executed add at the end of the linq query the method Load().

Question 31

Explain Repository Pattern

Answer 31

Mediates between the domain and data mapping layers, acting like an in-memory collection of domain objects.

Question 32

What is the Unit of work pattern

Answer 32

Maintains a list of objects affected by a business transaction and coordinates the writing out of changes.

Question 33

What is swagger

Answer 33

Is the way how to dotnet core documented the functionality of his endpoints