db模式的实体框架无法连接到服务器

Question

我正在尝试先使用 db 通过 db 实例连接，我创建了一个连接

 <add name="Entities" 
      connectionString="metadata=res://*/Models.ModelCmarket.csdl|res://*/Models.ModelCmarket.ssdl|res://*/Models.ModelCmarket.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(localdb)\v12.0;initial catalog=Cevaheer;integrated security=True;trustservercertificate=False;multisubnetfailover=True;MultipleActiveResultSets=True;multipleactiveresultsets=True;App=EntityFramework&quot;" 
      providerName="System.Data.EntityClient" />

而且我总是得到一个错误 -

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. The specified LocalDB instance does not exist.)

但如果我尝试

<add name="CevhermarketEntities" 
     connectionString="Data source=(localdb)\v12.0;initial catalog=Cevaheer;integrated security=True;trustservercertificate=False;multisubnetfailover=True;MultipleActiveResultSets=True;user id=dbuser;password=flexsin@123!;multipleactiveresultsets=True;"
     providerName="System.Data.SqlClient" /> 

我可以连接，也可以从 VS sql server explorer 和 SSMS 连接。

Answer 1

开始 - 有 4 个问题可能会导致 常见 LocalDb SqlExpress Sql Server 连接错误 SQL Network Interfaces, error: 50 - Local Database Runtime error occurred，在您开始之前need to rename the v11 or v12 to (localdb)\mssqllocaldb

• 你没有services running
• 你没有firelwall ports here 配置好了
• 您的安装存在问题/损坏（以下步骤有助于您从头开始）
• 你没有rename the V11 or 12 to mssqllocaldb

我发现最简单的方法是执行以下操作 - 我已附上图片和步骤以寻求帮助。

首先验证您安装了哪个实例，您可以通过检查注册表 和 运行cmd来做到这一点

1. cmd> Sqllocaldb.exe i
2. cmd> Sqllocaldb.exe s "whicheverVersionYouWantFromListBefore" 如果此步骤失败，您可以使用选项删除 d cmd> Sqllocaldb.exe d "someDb"
3. cmd> Sqllocaldb.exe c "createSomeNewDbIfyouWantDb" create - 图片错误
4. cmd> Sqllocaldb.exe start "createSomeNewDbIfyouWantDb"