Entity Framewor中的 Migration

http://www.entityframeworktutorial.net/code-first/code-based-migration-in-code-first.aspx = Code based Migration

http://www.entityframeworktutorial.net/code-first/automated-migration-in-code-first.aspx = Automated Migration

 

上边两篇文章分别介绍了DataMigration的两种方法。 下面简单总结一下步骤供自己使用。

VS Tools->package manager console

> enble-migration 

执行上面步骤将在你的DBContext目录下生成一个Migrations/Configuration.cs文件。这个文件的。 Seed方法是当Migration完成以后执行的插入数据库的操作，可以放一些系统运行所需要的必须得数据

 1 internal sealed class Configuration : DbMigrationsConfiguration<Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext>

 2     {

 3         public Configuration()

 4         {

 5             AutomaticMigrationsEnabled = true;

 6             ContextKey = "Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext";

 7         }

 8 

 9         protected override void Seed(Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext context)

10         {

11             //  This method will be called after migrating to the latest version.

12 

13             //  You can use the DbSet<T>.AddOrUpdate() helper extension method 

14             //  to avoid creating duplicate seed data. E.g.

15             //

16             //    context.People.AddOrUpdate(

17             //      p => p.FullName,

18             //      new Person { FullName = "Andrew Peters" },

19             //      new Person { FullName = "Brice Lambson" },

20             //      new Person { FullName = "Rowan Miller" }

21             //    );

22             //

23             context.Status.AddOrUpdate(p => p.Name,

24                 new Status { Name = "通过" },

25                 new Status { Name = "等待审批" }

26                 );

27         }

28     }

将以上构造函数Merge到自己的DBCOntext文件中

public MainDBUnitWorkContext(string connectionString)

: base(connectionString)

{

//this.Configuration.ProxyCreationEnabled = false;

this.Configuration.LazyLoadingEnabled = true;



Database.SetInitializer(new MigrateDatabaseToLatestVersion<MainDBUnitWorkContext,

Infrastructor.MainBoundedContext.Migrations.Configuration>("MyDBConnectionString"));

}

 

> Add-Migration "MyTest"

添加新的migration,执行完成以后在migration目录下生成一个 20150101_Mytest.cs文件，其内部列举了这次DB Upgrade执行的升级和降级的操作

> Update-DataBase -script: 参数script 是执生成sql脚本，也可以不要这个参数，将直接更新数据库