问题：Schema specified is not valid. Errors:
Model1.ssdl(2,2) : error 0152: No Entity Framework provider found for the ADO.NET provider with invariant name
'System.Data.SqlClient'. Make sure the provider is registered in the 'entityFramework' section of the application
config file. See http://go.microsoft.com/fwlink/?
原因：1.未引用EntityFramework.SqlServer.dll
2.引用的EF版本不正确
3.检查配置文件是否正确
app.config 中是否配置了该部分
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="v11.0" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
查看数据库配置的地方是否正确
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
4.dll文件是否在当前项目的bin文件夹下（因为我的就是这个愿因导致的，折腾了好久才找到）