1 //默认生成的数据表名为类名+字母s，这里使用TableAttribute来指定数据表名为T_Authors
 2     [Table("T_Authors")]
 3     public class Author
 4     {
 5         public int Id { set; get; }
 6         public string Name { set; get; }
 7         /*
 8         此处定义了Blog类型的属性，所以要确保Blog类中至少要有一个表示主键的字段，即public int Id { set; get; }。　　　　　　否则在生成数据表时会报错："EntityType 'Blog' has no key defined. Define the key for this EntityType.
 9 　　　　Blogs: EntityType: EntitySet 'Blogs' is based on type 'Blog' that has no keys defined."
10 　　　　*/
11         public virtual ICollection<Blog> Blogs { set; get; }
12     }
13
14     [Table("T_Blogs")]
15     public class Blog
16     {
17         public int Id { set; get; }
18         public string Title { set; get; }
19         public DateTime Time { set; get; }
20         public int AuthorId { set; get; }
21         public virtual Author Author { set; get; }
22     }
23
24     public class MyDbContext: DbContext
25     {
26          public MyDbContext()
27             : base("name=MyDbContext")
28         {
29         }
30         //DbContext会根据配置文件中connectionStrings指定的数据库名称来建立数据库
31         //DbContext根据DbSet属性的类型来创建数据表，这里指定了Author类型的属性，所以会生成T_Authors数据表
32         public virtual DbSet<Author> Authors { set; get; }
33     }

 1 <!--EF for MYSQL-->
 2 　<entityFramework codeConfigurationType="MySql.Data.Entity.MySqlEFConfiguration, MySql.Data.Entity.EF6">
 3     <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
 4     <providers>
 5       <provider invariantName="MySql.Data.MySqlClient" type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6" />
 6     </providers>
 7   </entityFramework>
 8   <connectionStrings>
 9     <add name="MyDbContext" connectionString="server=localhost;port=3306;database=EF;uid=root;password=root" providerName="System.Data.MySqlClient" />
10   </connectionStrings>

1 using (var db = new MyDbContext())
2 {
3     db.Authors.Add(new Author() { Name = "xfh" });
4     db.SaveChanges();
5 }

    [Table("T_Authors")]public class Author{public int Id { set; get; }public string Name { set; get; }public string Email { set; get; }public virtual ICollection<Blog> Blogs { set; get; }}

An unhandled exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll
The model backing the 'MyDbContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269).

 1 public partial class AddEmail : DbMigration
 2 {
 3     public override void Up()
 4     {
 5         //注意，这里数据表的名称是dbo.T_Blogs和dbo.T_Authors而不是我们指定的
 6         //T_Blogs和T_Authors，我们可以把数据表名称改为T_Blogs和T_Authors
 7         //数据表以dbo开头貌似是SQL SERVER中的命名方式，这里小编使用的是MYSQL
 8         CreateTable(
 9             "dbo.T_Blogs",
10             c => new
11                 {
12                     Id = c.Int(nullable: false, identity: true),
13                     Author_Id = c.Int(),
14                 })
15             .PrimaryKey(t => t.Id)
16             .ForeignKey("dbo.T_Authors", t => t.Author_Id)
17             .Index(t => t.Author_Id);
18
19         AddColumn("dbo.T_Authors", "Email", c => c.String(unicode: false));
20     }
21
22     public override void Down()
23     {
24         DropForeignKey("dbo.T_Blogs", "Author_Id", "dbo.T_Authors");
25         DropIndex("dbo.T_Blogs", new[] { "Author_Id" });
26         DropColumn("dbo.T_Authors", "Email");
27         DropTable("dbo.T_Blogs");
28     }
29 }
30     

public partial class AddEmail : DbMigration
{public override void Up(){AddColumn("T_Authors", "Email", c => c.String(unicode: false));}public override void Down(){DropColumn("T_Authors", "Email");}
}

public partial class AddAge : DbMigration
{public override void Up(){AddColumn("T_Authors", "Age", c => c.Int(nullable: false,defaultValue:18));}public override void Down(){DropColumn("T_Authors", "Age");}
}

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