EFPower tool 使用时发生的异常

EF Power Tool 可以从数据库反向出Model，可是在使用的过程中出现了一个奇怪的问题，第一次是正常的，后来不知什么原因，总是提示异常。异常信息如下：

System.Data.ProviderIncompatibleException: The provider did not return a ProviderManifestToken string. ---> System.InvalidOperationException: This operation requires a connection to the 'master' database. Unable to create a connection to the 'master' database because the original database connection has been opened and credentials have been removed from the connection string. Supply an unopened connection. ---> System.Data.SqlClient.SqlException: 用户 'sa' 登录失败。
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
   at System.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK)
   at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, SqlConnection owningObject)
   at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, TimeoutTimer timeout)
   at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, TimeoutTimer timeout, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at System.Data.SqlClient.SqlProviderServices.UsingConnection(SqlConnection sqlConnection, Action`1 act)
   at System.Data.SqlClient.SqlProviderServices.UsingMasterConnection(SqlConnection sqlConnection, Action`1 act)
   --- End of inner exception stack trace ---
   at System.Data.SqlClient.SqlProviderServices.UsingMasterConnection(SqlConnection sqlConnection, Action`1 act)
   at System.Data.SqlClient.SqlProviderServices.GetDbProviderManifestToken(DbConnection connection)
   at System.Data.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection)
   --- End of inner exception stack trace ---
   at System.Data.Common.DbProviderServices.GetProviderManifestToken(DbConnection connection)
   at System.Data.Entity.Design.EntityStoreSchemaGenerator.GetProviderSchemaMetadataWorkspace(DbProviderServices providerServices, DbConnection providerConnection)
   at System.Data.Entity.Design.EntityStoreSchemaGenerator.CreateStoreSchemaConnection(String providerInvariantName, String connectionString)
   at System.Data.Entity.Design.EntityStoreSchemaGenerator..ctor(String providerInvariantName, String connectionString, String namespaceName)
   at Microsoft.DbContextPackage.Handlers.ReverseEngineerCodeFirstHandler.ReverseEngineerCodeFirst(Project project)

后来发现，在连接数据库时，连接字符串中，要确保Persist Security Info=True;

因为成功那次，我选择了保存密码，这样就把Persist Security Info的值设置为True了。如果这个值为false，就是不保存密码，EF power tool 就没有办法连接数据库。