Linux Entity Framework Core 上的 SQL Server 连接字符串无效

Question

我使用的是 Linux，更具体地说是 Xubuntu。我已经在我的机器上安装了 SQL Server Express。我目前正在制作一个网络应用程序，但我的连接似乎无法正常工作，或者我不太了解所有内容，对吗？

我得到的输出是：

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: TCP Provider, error: 25 - Connection string is not valid)

我已经尝试了所有可能找到的方法，但没有任何效果。这可能是因为缺乏 Linux 用户的信息，但我仍然无法弄清楚。

一般来说，我正在尝试使用 EF 核心在我的控制台应用程序中使用连接字符串连接到我的本地 SQL 服务器。像这样：

internal const string CONNECTION_STRING =
            "Server = .\\SQLEXPRESS; Database = Questionnaires; Integrated Security = True";

这是我正在使用的连接字符串，应该可以工作。

我正在使用此命令在我的 SQL Server 上应用迁移并创建数据库：

dotnet ef database update 0 --project Data --startup-project WebInterface

我执行命令时得到的完整错误信息如下：

info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 2.2.3-servicing-35854 initialized 'QuestionnaireDbContext' using provider 'Microsoft.EntityFrameworkCore.SqlServer' with options: MigrationsAssembly=Migrations MigrationsHistoryTable=Migrations 
System.Data.SqlClient.SqlException (0x80131904): 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: TCP Provider, error: 25 - Connection string is not valid) ---> System.Net.Sockets.SocketException (0x80004005): Success
   at System.Data.SqlClient.SNI.SSRP.GetPortByInstanceName(String browserHostName, String instanceName)
   at System.Data.SqlClient.SNI.SNIProxy.CreateTcpHandle(DataSource details, Int64 timerExpire, Object callbackObject, Boolean parallel)
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling, String accessToken)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.Open()
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenDbConnection(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.<>c__DisplayClass18_0.<Exists>b__0(DateTime giveUp)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.<>c__DisplayClass12_0`2.<Execute>b__0(DbContext c, TState s)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, Func`2 operation, Func`2 verifySucceeded, TState state)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, TState state, Func`2 operation)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.Exists(Boolean retryOnNotExists)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_1.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
ClientConnectionId:00000000-0000-0000-0000-000000000000
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: TCP Provider, error: 25 - Connection string is not valid)

我应该得到的结果实际上是应用所有迁移并创建数据库。

Answer 1

Linux 有不同的命名管道概念。 .\\SQLSERVER 是 named pipe 符号。

此外，集成安全性在 Linux 上也不起作用（至少无需设置，但支持 Kerberos 身份验证），因为它与 Active Directory / NTML 授权有关。

所以使用常规的标准用户名授权连接字符串：

Server=localhost;Database=myDataBase;User Id=myUsername;Password=myPassword;

Answer 2

尝试使用：

Server = LOCALHOST\\SQLEXPRESS

代替：

Server = .\\SQLEXPRESS

这是因为服务器名称使用localhost 作为当前服务器，而文件路径使用. 作为当前文件夹的引用。

如果这不起作用，请确保 SQL Server 实例正在运行。这让我绊倒了很多次。

Answer 3

您似乎没有提供数据库服务器的完全限定名称。

在您的 SQL 服务器上编写以下查询，并检索实例名称

SELECT @@servername