ConnectionString、ConnectionTimeout、State プロパティの例 (VC + +)ConnectionString, ConnectionTimeout, and State Properties Example (VC++)

この例では、 ConnectionStringプロパティを使用して接続オブジェクトを開くさまざまな方法を示します。This example demonstrates different ways of using the ConnectionString property to open a Connection object. また、 ConnectionTimeoutプロパティを使用して接続タイムアウト期間を設定し、 stateプロパティを使用して接続の状態を確認します。It also uses the ConnectionTimeout property to set a connection timeout period, and the State property to check the state of the connections. このプロシージャを実行するには、GetState 関数が必要です。The GetState function is required for this procedure to run.

注意

Windows 認証をサポートするデータソースプロバイダーに接続する場合は、接続文字列にユーザー ID とパスワードの情報ではなく、 Trusted_Connection = yesまたはINTEGRATED Security = SSPIを指定する必要があります。If you are connecting to a data source provider that supports Windows authentication, you should specify Trusted_Connection=yes or Integrated Security = SSPI instead of user ID and password information in the connection string.

// ConnectionStringSampleCpp.cpp  
// compile with: /EHsc  
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")  
  
// Function declarations  
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};  
void ConnectionStringX();  
_bstr_t GetState(int intState);   
void PrintProviderError(_ConnectionPtr pConnection);  
void PrintComError(_com_error &e);  
  
int main() {  
   if (FAILED(::CoInitialize(NULL)))  
      return 0;  
  
   ConnectionStringX();  
   ::CoUninitialize();  
}  
  
void ConnectionStringX() {  
   // Define Connection object pointers.  Initialize pointers on define.  These are in the ADODB::  namespace  
   _ConnectionPtr pConnection1 = NULL;  
   _ConnectionPtr pConnection2 = NULL;  
   _ConnectionPtr pConnection3 = NULL;  
   _ConnectionPtr pConnection4 = NULL;  
  
   // Define Other Variables  
   HRESULT hr = S_OK;  
  
   try {  
      // Open a connection using OLE DB syntax.  
      TESTHR(pConnection1.CreateInstance(__uuidof(Connection)));  
      pConnection1->ConnectionString = "Provider='sqloledb';Data Source='(local)';"  
         "Initial Catalog='Pubs';Integrated Security='SSPI';";  
      pConnection1->ConnectionTimeout = 30;  
      pConnection1->Open("", "", "",adConnectUnspecified);  
      printf("cnn1 state: %s\n", (LPCTSTR)GetState(pConnection1->State));  
  
      // Open a connection using a DSN and ODBC tags.  
      // It is assumed that you have create DSN 'DataPubs' with a user name as   
      // 'MyUserId' and password as 'MyPassword'.  
      TESTHR(pConnection2.CreateInstance(__uuidof(Connection)));  
      pConnection2->ConnectionString = "DSN=DataPubs;UID=MyUserId;PWD=MyPassword;";  
      pConnection2->Open("", "", "", adConnectUnspecified);  
      printf("cnn2 state: %s\n", (LPCTSTR)GetState(pConnection2->State));  
  
      // Open a connection using a DSN and OLE DB tags.  
      TESTHR(pConnection3.CreateInstance(__uuidof(Connection)));  
      pConnection3->ConnectionString = "Data Source=DataPubs;";  
      pConnection3->Open("", "", "", adConnectUnspecified);  
      printf("cnn3 state: %s\n", (LPCTSTR)GetState(pConnection3->State));  
  
      // Open a connection using a DSN and individual arguments instead of a connection string.  
      // It is assumed that you have create DSN 'DataPubs' with a user name as   
      // 'MyUserId' and password as 'MyPassword'.  
      TESTHR(pConnection4.CreateInstance(__uuidof(Connection)));  
      pConnection4->Open("DataPubs", "MyUserId", "MyPassword", adConnectUnspecified);  
      printf("cnn4 state: %s\n", (LPCTSTR)GetState(pConnection4->State));  
   }  
   catch(_com_error &e) {  
      // Notify user of any errors.  Pass a connection pointer accessed from the Connection.  
      PrintProviderError(pConnection1);  
      if (pConnection2)  
         PrintProviderError(pConnection2);  
  
      if (pConnection3)  
         PrintProviderError(pConnection3);  
  
      if (pConnection4)  
         PrintProviderError(pConnection4);  
  
      PrintComError(e);  
   }  
  
   // Cleanup objects before exit.  
   if (pConnection1)  
      if (pConnection1->State == adStateOpen)  
         pConnection1->Close();  
  
   if (pConnection2)  
      if (pConnection2->State == adStateOpen)  
         pConnection2->Close();  
  
   if (pConnection3)  
      if (pConnection3->State == adStateOpen)  
         pConnection3->Close();  
  
   if (pConnection4)  
      if (pConnection4->State == adStateOpen)  
         pConnection4->Close();  
}  
  
_bstr_t GetState(int intState) {  
   _bstr_t strState;   
   switch(intState) {  
   case adStateClosed:  
      strState = "adStateClosed";  
      break;  
   case adStateOpen:  
      strState = "adStateOpen";  
      break;  
   default:  
      ;  
   }  
   return strState;  
}  
  
void PrintProviderError(_ConnectionPtr pConnection) {  
   // Print Provider Errors from Connection object.  
   // pErr is a record object in the Connection's Error collection.  
   ErrorPtr  pErr = NULL;  
  
   if ( (pConnection->Errors->Count) > 0) {  
      long nCount = pConnection->Errors->Count;  
  
      // Collection ranges from 0 to nCount -1.  
      for ( long i = 0 ; i < nCount ; i++ ) {  
         pErr = pConnection->Errors->GetItem(i);  
         printf("Error number: %x\t%s\n", pErr->Number, (LPCSTR)pErr->Description);  
      }  
   }  
}  
  
void PrintComError(_com_error &e) {  
   _bstr_t bstrSource(e.Source());  
   _bstr_t bstrDescription(e.Description());  
  
   // Print Com errors.    
   printf("Error\n");  
   printf("\tCode = %08lx\n", e.Error());  
   printf("\tCode meaning = %s\n", e.ErrorMessage());  
   printf("\tSource = %s\n", (LPCSTR) bstrSource);  
   printf("\tDescription = %s\n", (LPCSTR) bstrDescription);  
}  

参照See Also

Connection オブジェクト (ADO) Connection Object (ADO)
ConnectionString プロパティ (ADO) ConnectionString Property (ADO)
ConnectionTimeout プロパティ (ADO) ConnectionTimeout Property (ADO)
State プロパティ (ADO)State Property (ADO)