ASP.NET Core中使用EF Core（MySql）Code First

⒈添加依赖

　　MySql.Data.EntityFrameworkCore

⒉在appsettings.json配置文件中配置数据库连接字符串

 1 {
 2   "Logging": {
 3     "LogLevel": {
 4       "Default": "Warning"
 5     }
 6   },
 7   "ConnectionStrings": {
 8     "MySqlConnection": "server=localhost;port=3306;database=blog;user=root;password=admin"
 9   },
10   "AllowedHosts": "*"
11 }

⒊编写数据表实体类及上下文

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Threading.Tasks;
 5 
 6 namespace NewDb.Models
 7 {
 8     public class Blog
 9     {
10         public int BlogId { get; set; }
11         public string Url { get; set; }
12 
13         public ICollection<Post> Posts { get; set; }
14 
15     }
16 }

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Threading.Tasks;
 5 
 6 namespace NewDb.Models
 7 {
 8     public class Post
 9     {
10         public int PostId { get; set; }
11         public string Title { get; set; }
12         public string Content { get; set; }
13 
14         public int BlogId { get; set; }
15         public Blog Blog { get; set; }
16     }
17 }

 1 using Microsoft.EntityFrameworkCore;
 2 using System;
 3 using System.Collections.Generic;
 4 using System.Linq;
 5 using System.Threading.Tasks;
 6 
 7 namespace NewDb.Models
 8 {
 9     public class BloggingDbContext : DbContext
10     {
11         public BloggingDbContext(DbContextOptions<BloggingDbContext> options) : base(options) { }
12 
13         public DbSet<Blog> Blogs { get; set; }
14         public DbSet<Post> Posts { get; set; }
15     }
16 }

⒋使用依赖注入将上下文注册为服务

 1         public void ConfigureServices(IServiceCollection services)
 2         {
 3             services.Configure<CookiePolicyOptions>(options =>
 4             {
 5                 // This lambda determines whether user consent for non-essential cookies is needed for a given request.
 6                 options.CheckConsentNeeded = context => true;
 7                 options.MinimumSameSitePolicy = SameSiteMode.None;
 8             });
 9 
10 
11             services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
12 
13             var connection = Configuration["ConnectionStrings:MySqlConnection"];
14 
15             services.AddDbContext<BloggingDbContext>(options =>
16             {
17                 options.UseMySQL(connection);
18             });
19         }

⒌使用迁移创建数据库

　　第一种方式："Visual Studio 2019" >“工具”>“NuGet 包管理器”>“程序包管理器控制台”，执行以下命令

1 Add-Migration InitialCreate -v #搭建迁移基架，以便为模型创建一组初始表
2 Update-Database -v #创建数据库并向其应用新的迁移

　　第二种方式：使用.Net Core CLI，执行以下命令

1 dotnet ef migrations add InitialCreate -v #搭建迁移基架，以便为模型创建一组初始表
2 dotnet ef database update -v #创建数据库并向其应用新的迁移