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shortly DAO, ADO, ODBC, just do it

DataBase Access

shortly DAO, ADO, ODBC, just do it

by  Cagliostro  Posted    (Edited  )
The DAO and ADO codes are described with using ATL, because using OLE2 api directly is more routines than understandable code.

[color red]using ODBC:[/color]
Code: 
[color blue]#include[/color]<windows.h>
[color blue]#include[/color]<iostream>
[color blue]#include[/color]<string>
[color blue]#include[/color]<sql.h>
[color blue]#include[/color]<sqlext.h>
[color blue]using namespace[/color] std;
[color blue]int[/color] main()
{
  HENV hEnv;
  HDBC hDbc;
  RETCODE rc;
  [color blue]int[/color] iOut;
  [color blue]char[/color] strOut[256];
  [color blue]char[/color] szDSN[256] = "driver={Microsoft Access Driver (*.mdb)};dbq=[c:\\db1.mdb];";
  [color green]
  //dsn samples:
  //"driver={Microsoft Access Driver (*.mdb)};dbq=[f:\\db1.mdb];"
  //"driver={SQL Server};pwd={password there};Server={server name};Database={dbname there}"
  //driver names for different databases:
  //{SQL Server}
  //{Microsoft ODBC for Oracle}
  //{Oracle in oracle9}
  //{Microsoft Access Driver (*.mdb)}
  //{MySQL ODBC 3.51 Driver}
  [/color]

  [color blue]char[/color]* szSql = "select * from table1";
  rc = SQLAllocEnv(&hEnv);
  rc = SQLAllocConnect(hEnv, &hDbc);

  rc = SQLDriverConnect(hDbc, NULL, (unsigned char*)szDSN, 
      SQL_NTS, (unsigned char*)strOut, 
      255, (SQLSMALLINT*)&iOut, SQL_DRIVER_NOPROMPT);
  {
    [color blue]int[/color] ival;
    [color blue]char[/color] chval[128];
    [color blue]int[/color] ret1;
    [color blue]int[/color] ret2;
    HSTMT hStmt;
    rc = SQLAllocStmt(hDbc,&hStmt);
    rc = SQLPrepare(hStmt,(unsigned char*)szSql, SQL_NTS);[color green]//1
    //rc = SQLBindCol(hStmt, tab_column, tr_type, tr_value, tr_len, len_or_ind);[/color]
    rc = SQLBindCol(hStmt, 1, SQL_C_ULONG, &ival, 4, (SQLINTEGER*)& ret1);
    rc = SQLBindCol(hStmt, 2, SQL_C_CHAR, chval, 128, (SQLINTEGER*)&ret2);
    rc = SQLExecute(hStmt);[color green] //2[/color]
    [color green]
    //if you have queries like drop/create/many update... 
    //instead of //1 //2 and //3 you could use
    //rc=SQLExecDirectA(hStmt,(unsigned char*)szSql,SQL_NTS);
    [/color]
    cout<< ">table:"<< endl;
    [color blue]while[/color](1) [color green]//3[/color]
    {
      rc = SQLFetch(hStmt);
      [color blue]if[/color](rc != SQL_SUCCESS && rc != SQL_SUCCESS_WITH_INFO)[color blue]break[/color];
      cout<< "{"<< ival<<"}{"<< chval<< "}"<< endl;
    }
    rc=SQLFreeStmt(hStmt, SQL_DROP);
  }
  rc = SQLDisconnect(hDbc);
  rc = SQLFreeEnv(hEnv);
  [color blue]return[/color] 0;
}
//using ADO
Code: 
[color blue]#import[/color] "G:\Program Files\Common Files\System\ADO\msado15.dll"
[color blue]#include[/color] "Debug\msado15.tlh"
[color blue]#include[/color]<atlbase.h>
[color blue]#include[/color]<iostream>

[color blue]using namespace [/color]std;

[color blue]int[/color] main()
{
    CoInitialize(0);
    {
        HRESULT hr = -1;
        CComPtr<IUnknown> cnnobj;
        CComPtr<IUnknown> rdsnobj;
        CComPtr<IUnknown> errobj;
        hr = cnnobj.CoCreateInstance(L"ADODB.Connection.2.7");
        ADODB::_Connection* cnn;
        ADODB::_Recordset* rds;
        ADODB::Error* err;
        BSTR berr;
        ADODB::Fields* fds;
        ADODB::Field* fd1;
        ADODB::Field* fd2;

        
        hr = cnnobj->QueryInterface(&cnn);
        hr = cnn->Open(L"driver={Microsoft Access Driver (*.mdb)};dbq=[c:\\db1.mdb];", L"", L"", -1);
        
        hr = rdsnobj.CoCreateInstance(L"ADODB.Recordset.2.7");
        hr = rdsnobj->QueryInterface(&rds);

        hr = errobj.CoCreateInstance(L"ADODB.Error.2.7");
        hr = errobj->QueryInterface(&err);

        hr = rds->put_ActiveConnection(_variant_t(cnn));
        hr = rds->Open(_variant_t("select * from Table1"), _variant_t(cnn),  ADODB::adOpenUnspecified, ADODB::adLockUnspecified, -1);

        VARIANT_BOOL eof;
        VARIANT_BOOL bof;
        hr = rds->MoveFirst();
        hr = rds->get_Fields(&fds);
        hr = fds->get_Item(_variant_t(L"X"), &fd1);
        hr = fds->get_Item(_variant_t(L"Y"), &fd2);
        BSTR namex;
        BSTR namey;
        hr = fd1->get_Name(&namex);
        hr = fd2->get_Name(&namey);

        cout<< "filends count: "<< fds->GetCount()<< endl;
        wcout<< L"<"<< namex<< L"><"<< namey<< L">"<< endl;
        VARIANT valx, valy;
        [color blue]while[/color]([color blue]true[/color])
        {
            hr = rds->get_EOF(&eof);
            hr = rds->get_BOF(&bof);
            [color blue]if[/color](eof)[color blue]break[/color];
            [color blue]if[/color blue](bof)[color blue]break[/color];
            fd1->get_Value(&valx);
            fd2->get_Value(&valy);
            wcout<< L"{"<< ([color blue]wchar_t[/color]*)_bstr_t(_variant_t(valx))<< L"}{";
            wcout<< ([color blue]wchar_t[/color]*)_bstr_t(_variant_t(valy))<< L"}"<< endl;

            hr = rds->MoveNext();
        }
        hr = rds->Close();
        hr = cnn->Close();

    }
    CoUninitialize();
    [color blue]return[/color] 0;
}
[color red]using DAO[/color]
Code: 
[color blue]#import[/color] "G:\Program Files\Common Files\Microsoft Shared\DAO\dao360.dll"
[color blue]#include[/color] "Debug\dao360.tlh"
[color blue]#include[/color]<atlbase.h>
[color blue]#include[/color]<iostream>

[color blue]using namespace[/color] std;

[color blue]int[/color] main()
{
    CoInitialize(0);
    {
        HRESULT hr = -1;
        CComPtr<IUnknown> app;
        DAO::_DBEngine* eng;
        DAO::Workspace* wr;
        DAO::Database* db;
        DAO::Recordset* rs;
        VARIANT_BOOL eof;
        VARIANT_BOOL bof;
        DAO::Fields* fs;
        DAO::_Field* f1;
        DAO::_Field* f2;
        hr = app.CoCreateInstance(L"DAO.DBEngine.36");
        hr = app->QueryInterface(&eng);
        hr = eng->raw_CreateWorkspace(L"TestWorkSpace1", L"Admin", L"", _variant_t(DAO::dbUseJet), &wr);
        [color green]//open dbname, ifexclusive, ifreadonly, connect, retdb[/color]
        hr = wr->raw_OpenDatabase(_bstr_t(L"c:\\db1.mdb"), _variant_t(0), _variant_t(0), _variant_t(L""), &db);
        hr = db->raw_OpenRecordset(_bstr_t(L"select * from Table1"), 
            _variant_t(DAO::dbOpenDynaset), _variant_t(0), _variant_t(2), &rs);
        hr = rs->get_Fields(&fs);
        hr = fs->get_Item(_variant_t(0), &f1);
        hr = fs->get_Item(_variant_t(1), &f2);
        wcout<< L"<"<< (BSTR)f1->Name<< L"><" << f2->Name<< L">"<< endl;
        VARIANT valx, valy;
        [color blue]while[/color]([color blue]true[/color])
        {
            hr = rs->get_EOF(&eof);
            hr = rs->get_BOF(&bof);
            [color blue]if[/color](eof)[color blue]break[/color];
            [color blue]if[/color](bof)[color blue]break[/color];
            f1->get_Value(&valx);
            f2->get_Value(&valy);
            wcout<< L"{"<< (wchar_t*)_bstr_t(_variant_t(valx))<< L"}{";
            wcout<< (wchar_t*)_bstr_t(_variant_t(valy))<< L"}"<< endl;
            hr = rs->MoveNext();
        }

        hr = hr;
       
    }
    CoUninitialize();
    
    [color blue]return[/color] 0;
}
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