CoInitialize (NULL);//at the beginning of the COM component

Retrieves the hr;
Try
{
Hr=m_pConnection. CreateInstance (" ADODB. Connection ");//create a Connection object
If (SUCCEEDED (hr))
{
Hr=m_pConnection - & gt; Open (" Driver=PostgreSQL Unicode; Server=127.0.0.1; The Database=VersionManager; UID=test; The PWD=test ", ""," ", adModeUnknown);

If (FAILED (hr))
{
M_pConnection - & gt; Close ();
AfxMessageBox (" database connection failed. ");
return FALSE;
}
}
}
Catch _com_error (e)//catch exceptions
{
Cstrings errormessage;
Errormessage. Format (" connect to database failure! \ r \ n error message: % s ", e.E rrorMessage ());
AfxMessageBox (errormessage);//display an error message
}

SQL. The Format (" SELECT col_project_version FROM table_project_info WHERE col_project_name='% s' ", m_Name);
Try
{
M_pConnection - & gt; BeginTrans ();
Hr=m_pRecordset. CreateInstance (" ADODB. You ");
If (SUCCEEDED (hr))
{
Hr=m_pRecordset - & gt; Open ((_variant_t) SQL, variant_t ((IDispatch *) m_pConnection), adOpenDynamic, adLockOptimistic, adCmdText);
}
while (! M_pRecordset - & gt; AdoEOF)
{
Number=m_pRecordset - & gt; Col_project_version GetCollect (" ");//get data
SzVersion. The Format (" % s ", (LPCTSTR) _bstr_t (number));//the transformation output

M_pRecordset - & gt; MoveNext ();
}
M_pRecordset - & gt; Close ();
M_pConnection - & gt; CommitTrans ();
}
Catch _com_error (e)
{
AfxMessageBox (" connect to database failure!" );
M_pConnection - & gt; RollbackTrans ();
}
CoUninitialize ();//release com components

CodePudding user response:

The Debug step order see which function calls failed?

CodePudding user response:

Learn to debug is essential basic programming, it is recommended to use VS

CodePudding user response:

Hr=m_pRecordset - & gt; Open ((_variant_t) SQL, variant_t ((IDispatch *) m_pConnection), adOpenDynamic, adLockOptimistic, adCmdText);

Run the words, he went directly to the database connection failed. The front at the beginning of the COM and connect to the database is normal.

Catch _com_error (e)
{
AfxMessageBox (" connect to database failure!" );
M_pConnection - & gt; RollbackTrans ();
}
CoUninitialize ();//release com components

CodePudding user response:

Access, essentially, MySQL all have no problem, do not check PostgreSQL using ADO to connect to the database value...