1.开发环境中修改模型，在DbContext中加入静态构造函数，并设置初始化模式：

staticDemoDbContext()

{

Database.SetInitializer(new DropCreateDatabaseIfModelChanges());

}

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如果是Mysql，需要在DbContext加上 [DbConfigurationType(typeof(MySql.Data.Entity.MySqlEFConfiguration))] 属性，否则操作数据库时会报错，更改结束后，注释掉就可以了

新增类时需要在DbContext添加该类的引用属性，如：新增Department类：

public DbSet Departments { get; set; }

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2.生成环境中数据迁移

2.1 首先安装 Enitity Framework：Install-Package EntityFramework

2.2 修改DbContext静态构造函数：

staticDemoDbContext()

{

Database.SetInitializer(null);

}

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2.3 在程序包管理器控制台，执行语句：

PM> Enable-Migrations -EnableAutomaticMigrations

这时会在工程下建立文件夹：Migrations 和 Configuration.cs 文件

internal sealed class Configuration : DbMigrationsConfiguration{publicConfiguration()

{

AutomaticMigrationsEnabled= true;

}protected override voidSeed(MvcDemo.DAL.DemoDbContext context)

{//This method will be called after migrating to the latest version.//You can use the DbSet.AddOrUpdate() helper extension method//to avoid creating duplicate seed data. E.g.//

//context.People.AddOrUpdate(//p => p.FullName,//new Person { FullName = "Andrew Peters" },//new Person { FullName = "Brice Lambson" },//new Person { FullName = "Rowan Miller" }//);//}

}

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2.4 执行语句：(为测试效果，删除了Student类中的Email和Score属性)

PM> Add-Migration InitialCreate

此时会自动生成InitialCreate类：

usingSystem;usingSystem.Data.Entity.Migrations;public partial classInitialCreate : DbMigration

{public override voidUp()

{

DropColumn("dbo.Student", "Email");

DropColumn("dbo.Student", "Score");

}public override voidDown()

{

AddColumn("dbo.Student", "Score", c => c.Double(nullable: false));

AddColumn("dbo.Student", "Email", c => c.String(unicode: false));

}

}

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2.5 执行语句：Update-Database -Verbose 更改即应用到数据库中

2.6 新增类(表)

2.6.1 新增类 City，并在DbContext类中引用实例

public classCity

{public string ID { get; set; }public string Name { get; set; }

}

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2.6.2 执行语句

PM> Add-Migration AddCity

2.6.3 执行语句

PM> Update-Database -Verbose

查看数据，City表已经添加

3. 参考资料

4.源码