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

 internal sealed class Configuration : DbMigrationsConfiguration<Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext>
     {
         public Configuration()
         {
             AutomaticMigrationsEnabled = true;
             ContextKey = "Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext";
         }

         protected override void Seed(Infrastructor.MainBoundedContext.UnitWorks.MainDBUnitWorkContext context)
         {
             //  This method will be called after migrating to the latest version.

             //  You can use the DbSet<T>.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" }
             //    );
             //
             context.Status.AddOrUpdate(p => p.Name,
                 new Status { Name = "通过" },
                 new Status { Name = "等待审批" }
                 );
         }
     }

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