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Entity Framework (EF5, EF6) for working with a C database#
 SQL команды в Entity Framework 
посмотрели 8014 раз
обновлено: 2 Augusta 2018
В Entity Framework доступно также прямое выполнение sql-запросов.
Шаг 1. Создаем новое приложение
Шаг 2. Напишем код
  C#     Файл Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using System.Data.Entity;

namespace ConsoleApplication1
{
     public class Book
     {
          public int Id { get; set; }
          public string Name { get; set; }
          public int Price { get; set; }
     }

     class UserContext : DbContext
     {
          public UserContext()
               : base("MyConnection1")
          { }

          public DbSet<Book> Books { get; set; }
     }

     class Program
     {
          static void Main(string[] args)
          {
               // create db context
               using (UserContext db = new UserContext())
               {
                    // выбираем данные
                    System.Data.SqlClient.SqlParameter param = new System.Data.SqlClient.SqlParameter("@Name", "%кот%");
                    var items = db.Database.SqlQuery<Book>("SELECT * FROM Books WHERE Name LIKE @name", param);
                   
                    // показываем на экран данные
                    foreach (var item in items)
                         Console.WriteLine(item.Name);

                    // вставка
                    int numberOfRowInserted = db.Database.ExecuteSqlCommand("INSERT INTO Books (Name, Price) VALUES ('Хорошая книга', 5)");
              
                    // обновление
                    int numberOfRowUpdated = db.Database.ExecuteSqlCommand("UPDATE Books SET Name='Хоббиты' WHERE Id=2");
                   
                    // удаление
                    int numberOfRowDeleted = db.Database.ExecuteSqlCommand("DELETE FROM Books WHERE Id=1");
               }
          }
     }
}
Результат примера
 
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Creating and performing a Database migration to Entity Framework (I changed the c# class, then call EntityFramework\add-migration, i.e. the cs file with the migration code is automatically added to the project, then call EntityFramework\Update-Database, i.e. the migration file is executed and the database is changed)
 
Next topic →
Managing Transactions in the Entity Framework
 
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  Объявления  
  Объявления  
 
What is Entity Framework?
Types in Entity Framework
Entity Framework Type Conversion, Table Naming Conventions
Foreign Key and Cascade Deletion
DateTime & Date & Time Only in the Entity Framework
Code First
Code First. We"re writing a C# class. Entity Framework uses our C# class → to create and populate a table in the database
Auto Code First. Entity Framework creates a C# class from an existing table in the → database
Database First
Database First. Entity Framework creates a C# class from an existing table in the → database
Model First
Model First. We create a model in Visual Studio. Using the Entity Framework model, → creates C# classes and a Database
Working with data
Iterating over data in the Entity Framework
Adding Data to the Entity Framework
Modifying (editing) data in the Entity Framework
Deleting data in the Entity Framework
Database initialization and migration
Initialize the database in the Entity Framework. DropCreateDatabaseAlways allows you to repopulate the database with each new run
Performing a Database Migration to Entity Framework (if someone has already made a cs migration file, and I want to update the database on my computer, I perform the migration, that is, call EntityFramework\Update-Database)
Creating and performing a Database migration to Entity Framework (I changed the c# class, then call EntityFramework\add-migration, i.e. the cs file with the migration code is automatically added to the project, then call EntityFramework\Update-Database, i.e. the migration file is executed and the database is changed)
SQL in Entity Framework
SQL Commands in Entity Framework
Transactions in the Entity Framework
Managing Transactions in the Entity Framework
Additional topics, questions
What is <connectionStrings> a .config file for Entity Framework (EF5, EF6)
When EntityFrameworkUpdate-Database is called, the error "System.Data.SqlClient.SqlException (0x80131904) is thrown. A network-related or instance-specific error occurred while establishing a connection to SQL Server. "
When calling EntityFrameworkUpdate-Database, the error "Your startup project "..." doesn"t reference Microsoft.EntityFrameworkCore.Design"
WWW Sites to Learn Entity Framework
Sites to learn Entity Framework

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