如何避免使用移動服務對Azure主數據庫進行不必要的連接？

Question

以下代碼：

private void IsolateIssue() 
    { 
     using (var context = new SomeName.Models.MobileServiceContext()) 
     { 
      System.Diagnostics.Debug.WriteLine(context.Database.Connection.ConnectionString); 
      var numberOfItems = context.TodoItems.Count(); 
     } 
    } 

導致錯誤（主叫變種numberOfItems時）：

類型 'System.Data.SqlClient.SqlException' 的異常出現在 EntityFramework.dll但未在用戶代碼中處理其他 信息：無法打開登錄請求的數據庫「主」。 登錄失敗。用戶'SomeLoginName'登錄失敗。

這是我的connectionString：

「數據源= ServerName.database.windows.net;初始 目錄= SomeDataBaseName;用戶 ID = SomeLoginName;密碼= SomePassword};異步 加工=真; TrustServerCertificate = FALSE;」

很明顯，它無法連接到主數據庫。鑑於用戶名和密碼，我也無法使用LinqPad連接到主數據庫（當我嘗試出現類似錯誤時）。但是，它根本不應連接到主數據庫。當我嘗試使用Linqpad在SomeDataBaseName上登錄時，我成功獲取了todoItems（17）的數量。這證明根據給定的目的，根本不需要訪問主數據庫。

首先，我必須確保我可以獲取移動服務中的項目數量。我怎麼做？初始目錄顯示它應該連接到SomeDataBaseName，並且不需要連接到主數據庫以獲取項目數。我如何避免它試圖這樣做？

萬一有幫助，這裏是堆棧跟蹤：

堆棧跟蹤「在System.Data.SqlClient.SqlInternalConnection.OnError（SqlException異常，布爾breakConnection，行動1 wrapCloseInAction)\r\n at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)\r\n at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)\r\n at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)\r\n at System.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK)\r\n at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)\r\n at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)\r\n at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)\r\n at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData)\r\n at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)\r\n at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)\r\n at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)\r\n at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)\r\n at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)\r\n at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource 1重試，DbConnectionOptions USEROPTIONS，DbConnectionInternal &連接）\ r \ n at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection（DbConnection outerConnection，DbConnectionFactory connectionFactory，TaskCompletionSource 1 retry, DbConnectionOptions userOptions)\r\n at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource）System.Data.ProviderBase.DbConnectionFactory.TryGetConnection（DbConnection owningConnection，TaskCompletionSource 1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)\r\n at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource 1 retry，DbConnectionOptions userOptions）\ r \ n 1重試）\ r \ n在系統。 Data.SqlClient.SqlConnection.TryOpen（TaskCompletionSource 1 retry)\r\n at System.Data.SqlClient.SqlConnection.Open()\r\n at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<Open>b__36(DbConnection t, DbConnectionInterceptionContext c)\r\n at System.Data.Entity.Infrastructure.Interception.InternalDispatcher 1.Dispatch [TTarget，TInterceptionContext]（TTarget target，Action 2 operation, TInterceptionContext interceptionContext, Action 3 execution，Action 3 executed)\r\n at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext)\r\n at System.Data.Entity.SqlServer.SqlProviderServices.<>c__DisplayClass34.<UsingConnection>b__32()\r\n at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.<Execute>b__0()\r\n at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func 1 operation）\ r \ n at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute（Action操作）\ r \ n System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection（DbConnection sqlConnection，Action 1 act)\r\n at System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action 1 act）\ r \ n在System.Data.Entity.SqlServer.SqlProviderServices.DropDatabase（SqlConnection sqlConnection，Nullable 1 commandTimeout, String databaseName)\r\n at System.Data.Entity.SqlServer.SqlProviderServices.DbDeleteDatabase(DbConnection connection, Nullable 1 （System.Data.Entity.Core.Common.DbProviderServices.DeleteDatabase（DbConnection連接，可爲空1 commandTimeout, StoreItemCollection storeItemCollection)\r\n at System.Data.Entity.Core.Objects.ObjectContext.DeleteDatabase()\r\n at System.Data.Entity.Internal.DatabaseOperations.Delete(ObjectContext objectContext)\r\n at System.Data.Entity.Database.Delete()\r\n at System.Data.Entity.DropCreateDatabaseIfModelChanges 1.InitializeDatabase（TContext上下文）\ r \ n在System.Data.Entity.Internal.InternalContext 。 <> c__DisplayClassf 1.<CreateInitializationAction>b__e()\r\n at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)\r\n at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()\r\n at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c)\r\n at System.Data.Entity.Internal.RetryAction 1.PerformAction（TInput input）\ r \ n at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction（Action 1 action)\r\n at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()\r\n at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)\r\n at System.Data.Entity.Internal.Linq.InternalSet 1.Initialize（）\ r \ n在System.Data.Entity.Internal.Linq。 InternalSet 1.get_InternalContext()\r\n at System.Data.Entity.Infrastructure.DbQuery 1.System.Linq.IQueryable.get_Provider（）\ r \ n在System.Linq.Queryable。Count [TSource]（IQueryable`1 source）\ r \ n

Answer 1

我看到這個在你的堆棧中：System.Data.Entity.DropCreateDatabaseIfModelChanges。我相信EF需要訪問主數據庫才能刪除並重新創建數據庫。

本博客文章中提到的ClearDatabaseSchemaIfModelChanges初始化，它可以做你想做的：http://blogs.msdn.com/b/azuremobile/archive/2014/06/07/fresh-updates-to-azure-mobile-services-net.aspx