Type Property Example (Field) (VC++)

This example demonstrates the Type property by displaying the name of the constant that corresponds to the value of the Type property of all the Field objects in the Employees table. The FieldType function is required for this procedure to run.

Example

// BeginTypeFieldCpp.cpp  
// compile with: /EHsc  
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")  
  
#include <ole2.h>  
#include <stdio.h>  
#include <conio.h>  
  
// Function declarations  
inline void TESTHR(HRESULT x) { if FAILED(x) _com_issue_error(x); };  
  
void TypeX();  
_bstr_t FieldType(int intType);   
void PrintProviderError(_ConnectionPtr pConnection);  
void PrintComError(_com_error &e);  
  
int main() {  
   if ( FAILED(::CoInitialize(NULL)) )  
      return -1;  
  
   TypeX();  
   ::CoUninitialize();  
}  
  
void TypeX() {  
   // Define string variables.  
   _bstr_t strCnn("Provider='sqloledb'; Data Source='(local)'; Initial Catalog='pubs'; Integrated Security='SSPI';");  
  
   // Define ADO object pointers, initialize pointers.  These are in the ADODB:: namespace.  
   _RecordsetPtr pRstEmployees = NULL;  
   FieldsPtr pFldLoop = NULL;  
  
   try {    
      // Open recordset with data from Employee table.  
      TESTHR(pRstEmployees.CreateInstance(__uuidof(Recordset)));  
      pRstEmployees->Open ("employee", strCnn, adOpenForwardOnly, adLockReadOnly, adCmdTable);  
  
      printf("Fields in Employee Table:\n\n");  
  
      // Enumerate the Fields collection of the Employees table.  
      pFldLoop = pRstEmployees->GetFields();  
      for (short int intFields = 0 ; intFields < (int)pFldLoop->GetCount() ; intFields++) {  
         _variant_t Index;  
         Index.vt = VT_I2;  
         Index.iVal = intFields;  
         printf("  Name: %s\n" , (LPCSTR) pFldLoop->GetItem(Index)->GetName());  
         printf("  Type: %s\n\n", (LPCTSTR)FieldType(pFldLoop->GetItem(Index)->Type));  
      }  
   }  
   catch (_com_error &e) {  
      // Display errors, if any.  Pass connection pointer accessed from the Recordset.  
      _variant_t vtConnect = pRstEmployees->GetActiveConnection();  
  
      // GetActiveConnection returns connect string if connection  
      // is not open, else returns Connection object.  
      switch(vtConnect.vt) {  
      case VT_BSTR:  
         PrintComError(e);  
         break;  
      case VT_DISPATCH:  
         PrintProviderError(vtConnect);  
         break;  
      default:  
         printf("Errors occurred.");  
         break;  
      }  
   }  
  
   // Clean up objects before exit.  
   if (pRstEmployees)  
      if (pRstEmployees->State == adStateOpen)  
         pRstEmployees->Close();  
}  
  
_bstr_t FieldType(int intType) {  
   _bstr_t strType;   
   switch(intType) {  
   case adChar:  
      strType = "adChar";  
      break;  
   case adVarChar:  
      strType = "adVarChar";  
      break;  
   case adSmallInt:  
      strType = "adSmallInt";  
      break;  
   case adUnsignedTinyInt:  
      strType = "adUnsignedTinyInt";  
      break;  
   case adDBTimeStamp:  
      strType = "adDBTimeStamp";  
      break;  
   default:  
      break;  
   }  
   return strType;  
}  
  
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);  
}  

Fields in Employee Table:
Name: emp_id
Type: adChar
Name: fname
Type: adVarChar
Name: minit
Type: adChar
Name: lname
Type: adVarChar
Name: job_id
Type: adSmallInt
Name: job_lvl
Type: adUnsignedTinyInt
Name: pub_id
Type: adChar
Name: hire_date
Type: adDBTimeStamp

See Also

Field Object
Type Property (ADO)