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