1、为此示例创建一个控制台应用程序
1) 使用.NET Core命令行界面(CLI)初始化有效的.NET Core项目和控制台应用程序,然后切换到新创建的文件夹(mysqlefcore)
dotnet new console –o mysqlefcore
cd mysqlefcore
2) MySql.Data.EntityFrameworkCore 使用CLI 将包添加到应用程序
dotnet add package MySql.Data.EntityFrameworkCore --version 6.10.8
或者,您可以使用Visual Studio中的程序包管理器控制台添加程序包:
Install-Package MySql.Data.EntityFrameworkCore -Version 6.10.8
注意
版本(例如6.10.8)必须与您使用的实际Connector / NET版本匹配。有关当前版本信息,请参阅 表9.2“支持的Entity Framework Core版本”。
3) 恢复项目文件中指定的依赖项和项目特定工具
dotnet restore
2、创建模型并运行应用程序
控制器应用程序将使用此EF Core示例中的模型。它由两个与书库相关的实体组成,这些实体将在 LibraryContext类(或数据库上下文)中配置。
1) 创建一个名为的新文件LibraryModel.cs
,然后将以下Book和 Publisher类添加到 mysqlefcore
命名空间
namespace mysqlefcore
{
public class Book
{
public string ISBN { get; set; }
public string Title { get; set; }
public string Author { get; set; }
public string Language { get; set; }
public int Pages { get; set; }
public virtual Publisher Publisher { get; set; }
}
public class Publisher
{
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Book> Books { get; set; }
}
}
2) 创建一个名为的新文件LibraryContext.cs
并添加后面的代码。将通用连接字符串替换为适合MySQL服务器配置的字符串
该LibraryContext class 实体使用,它使模型的特定属性,如Key,所需的列,引用等的配置。
using Microsoft.EntityFrameworkCore;
using MySQL.Data.EntityFrameworkCore.Extensions;
namespace mysqlefcore
{
public class LibraryContext : DbContext
{
public DbSet<Book> Book { get; set; }
public DbSet<Publisher> Publisher { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseMySQL("server=localhost;database=library;user=user;password=password");
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Publisher>(entity =>
{
entity.HasKey(e => e.ID);
entity.Property(e => e.Name).IsRequired();
});
modelBuilder.Entity<Book>(entity =>
{
entity.HasKey(e => e.ISBN);
entity.Property(e => e.Title).IsRequired();
entity.HasOne(d => d.Publisher)
.WithMany(p => p.Books);
});
}
}
}
3) 将以下代码插入现有 Program.cs
文件,替换默认的C#代码
using Microsoft.EntityFrameworkCore; using System; using System.Text; namespace mysqlefcore { class Program { static void Main(string[] args) { InsertData(); PrintData(); } private static void InsertData() { using(var context = new LibraryContext()) { // Creates the database if not exists context.Database.EnsureCreated(); // Adds a publisher var publisher = new Publisher { Name = "Mariner Books" }; context.Publisher.Add(publisher); // Adds some books context.Book.Add(new Book { ISBN = "978-0544003415", Title = "The Lord of the Rings", Author = "J.R.R. Tolkien", Language = "English", Pages = 1216, Publisher = publisher }); context.Book.Add(new Book { ISBN = "978-0547247762", Title = "The Sealed Letter", Author = "Emma Donoghue", Language = "English", Pages = 416, Publisher = publisher }); // Saves changes context.SaveChanges(); } } private static void PrintData() { // Gets and prints all books in database using (var context = new LibraryContext()) { var books = context.Book .Include(p => p.Publisher); foreach(var book in books) { var data = new StringBuilder(); data.AppendLine($"ISBN: {book.ISBN}"); data.AppendLine($"Title: {book.Title}"); data.AppendLine($"Publisher: {book.Publisher.Name}"); Console.WriteLine(data.ToString()); } } } } }
4) 使用以下CLI命令还原依赖项,然后运行该应用程序
dotnet restore
dotnet run
运行应用程序的输出:
ISBN: 978-0544003415
Title: The Lord of the Rings
Publisher: Mariner Books
ISBN: 978-0547247762
Title: The Sealed Letter
Publisher: Mariner Books
参考文档:https://dev.mysql.com/doc/connector-net/en/connector-net-entityframework-core-example.html