odbc_testdlg.cpp

ODBC编程

// ODBC_TESTDlg.cpp : implementation file
//

#include "stdafx.h"
#include "ODBC_TEST.h"
#include "ODBC_TESTDlg.h"

#include <sql.h> 
#include <sqlext.h> 

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CODBC_TESTDlg dialog

CODBC_TESTDlg::CODBC_TESTDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CODBC_TESTDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CODBC_TESTDlg)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CODBC_TESTDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CODBC_TESTDlg)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CODBC_TESTDlg, CDialog)
	//{{AFX_MSG_MAP(CODBC_TESTDlg)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_BUTTON, OnButtonExcute)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CODBC_TESTDlg message handlers

BOOL CODBC_TESTDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
	SetDlgItemText(IDC_EDIT_USERNAME, "sa");
	SetDlgItemText(IDC_EDIT_PASSWORD, "sa");
	SetDlgItemText(IDC_EDIT_SQL, "SELECT SNO, SNAME FROM S");
	SetDlgItemText(IDC_EDIT_DSN, "student-sql");
	
	return TRUE;  // return TRUE  unless you set the focus to a control
}

// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CODBC_TESTDlg::OnPaint() 
{
	if (IsIconic())
	{
		CPaintDC dc(this); // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	else
	{
		CDialog::OnPaint();
	}
}

// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CODBC_TESTDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

void CODBC_TESTDlg::OnButtonExcute() 
{
	HENV	henv = NULL;//句柄声名,此句柄为环境句柄
	HDBC	hdbc = NULL;//句柄声名，此句柄为连接句柄
	HSTMT	hstmt = NULL;//句柄声名

	SQLINTEGER   sNo, cbNo, cbName;
	SQLCHAR szName[50];//主机名
	SQLCHAR szDSN[100] ;//数据源名
	SQLCHAR szSelect[1000];//SOL语句
	SQLCHAR szUID[100];		//log name，是什么意思，
	SQLCHAR	szAuthStr[20];	//passward

	::ZeroMemory(szName,sizeof(szName));//很想知道这一行是什么意思，有什么作用;
	::ZeroMemory(szDSN,sizeof(szDSN));
	::ZeroMemory(szSelect,sizeof(szSelect));
	::ZeroMemory(szUID,sizeof(szUID));
	::ZeroMemory(szAuthStr,sizeof(szAuthStr));

	CString strTemp(_T(""));
	strTemp.Empty();//将文本中的信息取下，赋于szUID，以下同理。
	GetDlgItemText(IDC_EDIT_USERNAME, strTemp);
	strcpy((char*)szUID, strTemp);

	strTemp.Empty();
	GetDlgItemText(IDC_EDIT_PASSWORD, strTemp);
	strcpy((char*)szAuthStr, strTemp);

	strTemp.Empty();
	GetDlgItemText(IDC_EDIT_DSN, strTemp);
	strcpy((char*)szDSN, strTemp);

	strTemp.Empty();
	GetDlgItemText(IDC_EDIT_SQL, strTemp);
	strcpy((char*)szSelect, strTemp);

	RETCODE	retcode;
	SQLAllocEnv(&henv);		/*分配环境句柄*/   //
	SQLAllocConnect(henv, &hdbc);/*分配连接句柄*/
	
   	CString strMsg(_T("")); //存放Message

	//连接数据库
	retcode=SQLConnect(hdbc,
						(SQLCHAR*)szDSN,	(SWORD)strlen((char*)szDSN),//数据源
						(SQLCHAR*)szUID,	(SWORD)strlen((char*)szUID),//用户名
						(SQLCHAR*)szAuthStr, (SWORD)strlen((char*)szAuthStr)//登录密码
						);
	if((retcode == SQL_SUCCESS ) ||(retcode == SQL_SUCCESS_WITH_INFO))
	{
		TRACE0("Open database Succeed !\n") ; //TRACEO()是什么意思，有什么作用，和MessageBox（）有什么区别。是不是都有提示作用。？
	}
	else
	{
		TRACE0("Open database Failed  !\n") ; 
		/* Print the errmsg*/
		 strMsg.Format("Open database Failed  !\n");
		 AfxMessageBox(strMsg);

		SQLFreeEnv(henv);		/*当完成应用后，释放环境句柄*/
		return ;

	}

	SQLAllocStmt(hdbc,&hstmt);		/*分配语句句柄*/

	/*执行SQL语句*/
	retcode = SQLExecDirect(hstmt,szSelect,  SQL_NTS);
	if (retcode == SQL_SUCCESS) 
	{
		int iCount = 0;

		/*结果集处理*/
		while (TRUE)
		{
	      retcode = SQLFetch(hstmt);

		  if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
		  {
  			  iCount++;		  
	         /* Get data for columns 1, 2, and 3 */
		     SQLGetData(hstmt, 1, SQL_C_ULONG, &sNo, 0, &cbNo);
			 SQLGetData(hstmt, 2, SQL_C_CHAR, szName, 50, &cbName);

			 strMsg.Format("result record %d: %d, %s", iCount, sNo, szName);
			 AfxMessageBox(strMsg);//如果有多行语句，那不是要弹出多个Message（），为什么不用ListCtril
		  }
		  else 
		  {
			break;
		  }
		}
	}
	else
	{
		strMsg.Format("SQLExecDirect Failed!");
		AfxMessageBox(strMsg);
	}

	//释放语句句柄
	if(hstmt != NULL) 
	{ 
		SQLFreeStmt(hstmt,SQL_DROP) ; 
		hstmt = NULL ; 
	}

	SQLDisconnect(hdbc);	/*断开数据源*/
	SQLFreeConnect(hdbc);	/*释放连接句柄*/
	SQLFreeEnv(henv);		/*当完成应用后，释放环境句柄*/
	
}