实体框架迁移 - 支持动态连接字符串

Question

我无法让迁移适用于特定场景。

我们的应用程序使用两种不同的模型。第一个是主数据库，在那里，迁移工作正常。第二种模型适用于我们的客户数据库，它针对每个客户（当然......）但都共享相同的模型。

因此，在应用程序 (ASP.Net MVC 3) 中，我们使用路由识别客户，并且所有客户都托管在同一个应用程序中。因此，对于每个请求，我们将一个密钥传递给我们的客户模型 dbContext 构造函数，并使用该密钥通过一个简单的辅助方法恢复连接字符串。

应用程序工作正常，但迁移不正常，因为我发现无法在包管理器控制台中传递密钥。

我尝试创建自己的 IDbConnectionFactory，但没有考虑在内。

如果我尝试使用连接工厂的更新数据库命令，我会收到以下错误，这是正常的，因为没有传递任何密钥，但我可以看到我的连接工厂正在启动 (EFCustomerModel.EFConnectionFactory)：

PM> update-database  -verbose
Using NuGet project 'EFCustomerModel'.
Using StartUp project 'PMEL.DatabaseSetup'.
System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0.
   at System.Data.Common.DbConnectionOptions.GetKeyValuePair(String connectionString, Int32 currentPosition, StringBuilder buffer, Boolean useOdbcRules, String& keyname, String& keyvalue)
   at System.Data.Common.DbConnectionOptions.ParseInternal(Hashtable parsetable, String connectionString, Boolean buildChain, Hashtable synonyms, Boolean firstKey)
   at System.Data.Common.DbConnectionOptions..ctor(String connectionString, Hashtable synonyms, Boolean useOdbcRules)
   at System.Data.SqlClient.SqlConnectionString..ctor(String connectionString)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnectionOptions(String connectionString, DbConnectionOptions previous)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnectionPoolGroup(String connectionString, DbConnectionPoolGroupOptions poolOptions, DbConnectionOptions& userConnectionOptions)
   at System.Data.SqlClient.SqlConnection.ConnectionString_Set(String value)
   at System.Data.SqlClient.SqlConnection.set_ConnectionString(String value)
   at System.Data.SqlClient.SqlConnection..ctor(String connectionString)
   **at EFCustomerModel.EFConnectionFactory.CreateConnection(String nameOrConnectionString) in C:\...\EFCustomerModel\EFConnectionFactory.vb:line 18**
   at System.Data.Entity.Internal.LazyInternalConnection.Initialize()
   at System.Data.Entity.Internal.LazyInternalConnection.get_Connection()
   at System.Data.Entity.Internal.LazyInternalContext.get_Connection()
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbProviderInfo modelProviderInfo, AppConfig config, DbConnectionInfo connectionInfo)
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.GetMigrator()
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.RunCore()
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.Run()
Format of the initialization string does not conform to specification starting at index 0.

但是当我尝试使用 -ConnectionString 参数传入我的密钥时，我的连接工厂被忽略了，我得到了同样的错误：

PM> update-database  -verbose -ConnectionString:CC99999 -ConnectionProviderName:System.Data.SqlClient
Using NuGet project 'EFCustomerModel'.
Using StartUp project 'PMEL.DatabaseSetup'.
System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0.
   at System.Data.Common.DbConnectionOptions.GetKeyValuePair(String connectionString, Int32 currentPosition, StringBuilder buffer, Boolean useOdbcRules, String& keyname, String& keyvalue)
   at System.Data.Common.DbConnectionOptions.ParseInternal(Hashtable parsetable, String connectionString, Boolean buildChain, Hashtable synonyms, Boolean firstKey)
   at System.Data.Common.DbConnectionOptions..ctor(String connectionString, Hashtable synonyms, Boolean useOdbcRules)
   at System.Data.SqlClient.SqlConnectionString..ctor(String connectionString)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnectionOptions(String connectionString, DbConnectionOptions previous)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnectionPoolGroup(String connectionString, DbConnectionPoolGroupOptions poolOptions, DbConnectionOptions& userConnectionOptions)
   at System.Data.SqlClient.SqlConnection.ConnectionString_Set(String value)
   at System.Data.SqlClient.SqlConnection.set_ConnectionString(String value)
   at System.Data.Entity.Internal.LazyInternalConnection.InitializeFromConnectionStringSetting(ConnectionStringSettings appConfigConnection)
   at System.Data.Entity.Internal.LazyInternalConnection.Initialize()
   at System.Data.Entity.Internal.LazyInternalConnection.get_Connection()
   at System.Data.Entity.Internal.LazyInternalContext.get_Connection()
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbProviderInfo modelProviderInfo, AppConfig config, DbConnectionInfo connectionInfo)
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbConnectionInfo connectionInfo)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.GetMigrator()
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.RunCore()
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.Run()
Format of the initialization string does not conform to specification starting at index 0.

那么，这是迁移中不受支持的场景，还是有另一种方法可以传入我的密钥，或者可能有另一种方法来生成我的连接字符串？

Answer 1

您应该能够使用-ConnectionStringName 参数将密钥传递给您的自定义连接工厂。该参数将被传递给CreateConnection 方法。

另一种可能的解决方案是从您的代码中调用数据库迁移：

var configuration = new Configuration();
configuration.TargetDatabase = new DbConnectionInfo(
    "Server=MyServer;Database=MyDatabase;Trusted_Connection=True;", 
    "System.Data.SqlClient");

var migrator = new DbMigrator(configuration);
migrator.Update();