在程序集“SMSApp”中发现了不止一种迁移配置类型。指定要使用的名称

我正在使用代码优先方法开发 mvc 5 应用程序。

我面临一个问题。第一次当我尝试下面的命令时，它起作用并在该数据库中生成表。但是当我更改了更多类，然后尝试前两个查询时，它在这种情况下有效，但是当我尝试第三个命令时，它给了我这条消息。

First step
==========

enable-migrations -ContextTypeName IdentityDb -MigrationsDirectory DAL\IdentityMigrations

enable-migrations -ContextTypeName SMSContext -MigrationsDirectory DAL\SMSMigrations

Second Step
===========

add-migration -ConfigurationTypeName SMSApp.DAL.IdentityMigrations.Configuration "InitialCreate"

add-migration -ConfigurationTypeName SMSApp.DAL.SMSMigrations.Configuration "InitialCreate"

Third Step
==========

update-database -ConfigurationTypeName SMSApp.DAL.IdentityMigrations.Configuration -verbose

update-database -ConfigurationTypeName SMSApp.DAL.SMSMigrations.Configuration -verbose

  

看到第一个错误：

PM> add-migration -ConfigurationTypeName SMSApp.DAL.IdentityMigrations.Configuration "InitialCreate"
Scaffolding migration ' '.
The Designer Code for this migration file includes a snapshot of your current Code First model. This snapshot is used to calculate the changes to your model when you scaffold the next migration. If you make additional changes to your model that you want to include in this migration, then you can re-scaffold it by running 'Add-Migration InitialCreate' again.

A previous migration called 'InitialCreate' was already applied to the target database. If you meant to re-scaffold 'InitialCreate', revert it by running 'Update-Database -TargetMigration $InitialDatabase', then delete '201409261933262_InitialCreate1.cs' and run 'Add-Migration InitialCreate' again.

之后我执行了以下命令，它给出了以下异常。

更新数据库 -TargetMigration $InitialDatabase -verbose

PM> Update-Database -TargetMigration $InitialDatabase -verbose
Using StartUp project 'SMSApp'.
Using NuGet project 'SMSApp'.
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
System.Data.Entity.Migrations.Infrastructure.MigrationsException: More than one migrations configuration type was found in the assembly 'SMSApp'. Specify the name of the one to use.
   at System.Data.Entity.Utilities.TypeFinder.FindType(Type baseType, String typeName, Func`2 filter, Func`2 noType, Func`3 multipleTypes, Func`3 noTypeWithName, Func`3 multipleTypesWithName)
   at System.Data.Entity.Migrations.Utilities.MigrationsConfigurationFinder.FindMigrationsConfiguration(Type contextType, String configurationTypeName, Func`2 noType, Func`3 multipleTypes, Func`3 noTypeWithName, Func`3 multipleTypesWithName)
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.FindConfiguration()
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.GetMigrator()
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Update(String targetMigration, Boolean force)
   at System.Data.Entity.Migrations.UpdateDatabaseCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
More than one migrations configuration type was found in the assembly 'SMSApp'. Specify the name of the one to use.

现在我很担心如何解决？

您需要指定更新数据库时要使用的配置。

Update-Database -ConfigurationTypeName MyRenamedConfiguration