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VC++ 访问数据库实例详解图解

發布時間：2025/4/14 c/c++ 16 豆豆

生活随笔收集整理的這篇文章主要介紹了 VC++ 访问数据库实例详解图解小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

一 ADO 方式訪問 Access

新建一個對話框工程，添加控件，如圖；

創建Access數據庫如圖；

應用程序啟動時進行COM初始化；

BOOL CDemoApp::InitInstance()
{
if (!SUCCEEDED(CoInitialize(NULL)))
{
::AfxMessageBox(_T("Failed to initialize COM!"));
return FALSE;
}

AfxEnableControlContainer();

對話框類實現文件代碼如下；

// DemoDlg.cpp : implementation file
// Download by http://www.NewXing.com

#include "stdafx.h"
#include "Demo.h"
#include "DemoDlg.h"

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

/
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
CAboutDlg();

// Dialog Data
//{{AFX_DATA(CAboutDlg)
enum { IDD = IDD_ABOUTBOX };
//}}AFX_DATA

// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CAboutDlg)
protected:
virtual void DoDataExchange(CDataExchange* pDX); ? ?// DDX/DDV support
//}}AFX_VIRTUAL

// Implementation
protected:
//{{AFX_MSG(CAboutDlg)
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
//{{AFX_DATA_INIT(CAboutDlg)
//}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CAboutDlg)
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
//{{AFX_MSG_MAP(CAboutDlg)
// No message handlers
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/
// CDemoDlg dialog

CDemoDlg::CDemoDlg(CWnd* pParent /*=NULL*/)
: CDialog(CDemoDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CDemoDlg)
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);

if (!SUCCEEDED(m_pConnection.CreateInstance(__uuidof(Connection))))
{
m_pConnection = NULL;
TRACE(_T("Database CreateInstance failed"));
}

if (!SUCCEEDED(m_pRecordset.CreateInstance(__uuidof(Recordset))))
{
m_pRecordset = NULL;
TRACE(_T("Recordset CreateInstance Failed!"));
}

//打開數據庫
CString strConnect = _T("Provider=Microsoft.Jet.OLEDB.4.0;Data Source= Demo.mdb");
if (!OpenDatabase(strConnect))
{
AfxMessageBox(_T("數據庫打開失敗。"));
return;
}

//打開記錄集
if (!OpenRecordset(_T("SELECT * FROM DemoTable")))
{
AfxMessageBox(_T("記錄集打開失敗。"));
return;
}
}

CDemoDlg::~CDemoDlg()
{
m_pRecordset->Close();
m_pConnection->Close();
}

void CDemoDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CDemoDlg)
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CDemoDlg, CDialog)
//{{AFX_MSG_MAP(CDemoDlg)
ON_WM_SYSCOMMAND()
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDC_FIND, OnFind)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/
// CDemoDlg message handlers

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

// Add "About..." menu item to system menu.

// IDM_ABOUTBOX must be in the system command range.
ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
ASSERT(IDM_ABOUTBOX < 0xF000);

CMenu* pSysMenu = GetSystemMenu(FALSE);
if (pSysMenu != NULL)
{
CString strAboutMenu;
strAboutMenu.LoadString(IDS_ABOUTBOX);
if (!strAboutMenu.IsEmpty())
{
pSysMenu->AppendMenu(MF_SEPARATOR);
pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
}
}

// 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

//初始化ListCtrl
CListCtrl* pListCtrl = (CListCtrl*)GetDlgItem(IDC_LIST);
pListCtrl->SetExtendedStyle(LVS_EX_FULLROWSELECT | LVS_EX_GRIDLINES);
pListCtrl->InsertColumn(1, _T("序號"), LVCFMT_CENTER, 80);
pListCtrl->InsertColumn(2, _T("姓名"), LVCFMT_CENTER, 100);
pListCtrl->InsertColumn(3, _T("年齡"), LVCFMT_CENTER, 100);

return TRUE;
}

void CDemoDlg::OnSysCommand(UINT nID, LPARAM lParam)
{
if ((nID & 0xFFF0) == IDM_ABOUTBOX)
{
CAboutDlg dlgAbout;
dlgAbout.DoModal();
}
else
{
CDialog::OnSysCommand(nID, lParam);
}
}

// 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 CDemoDlg::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 CDemoDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}

BOOL CDemoDlg::OpenDatabase(LPCTSTR lpszConnect, long nOptions)
{
ASSERT(m_pConnection != NULL);
ASSERT(lpszConnect != NULL);
ASSERT(AfxIsValidString(lpszConnect));

//打開數據庫連接
try
{
return SUCCEEDED(m_pConnection->Open(_bstr_t(lpszConnect),?
_T(""), _T(""), nOptions));
}
catch (_com_error& e)
{
TRACE(_T("%s\n"), e.ErrorMessage());
return FALSE;
}
}

BOOL CDemoDlg::CloseDatabase()
{
ASSERT(m_pConnection != NULL);

//關閉數據庫連接
try
{
if (m_pConnection->State & adStateOpen)?
{
return SUCCEEDED(m_pConnection->Close());
}
else
{
return TRUE;
}
}
catch (_com_error& e)
{
TRACE(_T("%s\n"), e.ErrorMessage());
return FALSE;
}?
}

BOOL CDemoDlg::OpenRecordset(LPCTSTR lpszSource, long nCursorType, long nLockType, long nOptions)
{
ASSERT(m_pConnection != NULL);
ASSERT(m_pRecordset != NULL);
ASSERT(lpszSource != NULL);
ASSERT(AfxIsValidString(lpszSource));

//打開記錄集
try
{
return (SUCCEEDED(m_pRecordset->Open(_variant_t(lpszSource),
m_pConnection.GetInterfacePtr(),
(CursorTypeEnum)nCursorType,?
(LockTypeEnum)nLockType,
nOptions)));
}
catch(_com_error e)
{
TRACE(_T("%s\n"), e.ErrorMessage());
return FALSE;
}
}

BOOL CDemoDlg::CloseRecorset()
{
ASSERT(m_pRecordset != NULL);

//關閉記錄集
try
{
if (m_pRecordset->State & adStateOpen)?
{
return SUCCEEDED(m_pRecordset->Close());
}
else
{
return TRUE;
}
}
catch (_com_error e)
{
TRACE(_T("%s\n"), e.ErrorMessage());
return FALSE;
}
}

void CDemoDlg::OnFind()?
{
if (!(m_pRecordset->State & adStateOpen))
{
AfxMessageBox((_T("記錄集未打開。")));
return;
}

//查找條件
CString strCriteria = _T("");
CString strName = _T("");
GetDlgItemText(IDC_NAME, strName);
strCriteria.Format(_T("NAME like '%s'"), strName);

//查找記錄集
CListCtrl* pListCtrl = (CListCtrl*)GetDlgItem(IDC_LIST);
pListCtrl->DeleteAllItems();
if (m_pRecordset->BOF && m_pRecordset->adoEOF)
{
return;
}
m_pRecordset->MoveFirst();
int n = 0;
m_pRecordset->Find(_bstr_t(strCriteria), 0, adSearchForward);
while (!m_pRecordset->adoEOF)
{
_variant_t varValue;
CString strName = _T("");
int nAge = 0;

varValue = m_pRecordset->GetCollect(_variant_t(_T("NAME")));
if (varValue.vt != VT_NULL)
{
strName = varValue.bstrVal;
}
else
{
strName = _T("");
}

varValue = m_pRecordset->GetCollect(_variant_t(_T("AGE")));
if (varValue.vt != VT_NULL)
{
nAge = varValue.intVal;
}
else
{
nAge = 0;
}

//刷新ListCtrl
CString strText = _T("");
strText.Format(_T("%d"), n + 1);
pListCtrl->InsertItem(n, strText);
strText.Format(_T("%s"), strName);
pListCtrl->SetItemText(n, 1, strText);
strText.Format(_T("%d"), nAge);
pListCtrl->SetItemText(n, 2, strText);
n++;

m_pRecordset->Find(_bstr_t(strCriteria), 1, adSearchForward);
}
}

折疊起來看下函數；

代碼就不解釋了；函數含義比較明確；除了操作數據庫，ADO方式還有COM相關操作；

效果：

VC在調試時，Data Source= Demo.mdb，這樣的語句，訪問的不是Debug目錄下的Demo.mdb，是和Debug目錄同級；

如果Debug目錄同級沒有數據庫，則打開數據庫失敗；

工程下載

http://pan.baidu.com/s/1slEEOMD

Access工具下載

http://blog.csdn.net/bcbobo21cn/article/details/51000041

VC6下載

http://blog.csdn.net/bcbobo21cn/article/details/44200205

二 VC 訪問 sqlite3

首先用sqlite3創建一個數據庫，設備db；

創建表并插入數據；

接下來在VC6中新建一個控制臺工程；

代碼；

#include <stdio.h>?
#include <stdlib.h>?
#include <sqlite3.h>?
int column_names_printed = 0;?
void print_row(int n_values, char** values)?
{?
? ? int i;?
? ? for (i = 0; i < n_values; ++i) {?
? ? ? ? printf("%10s", values[i]);?
? ? }?
? ? printf("\n");?
}?
int print_result(void* data, int n_columns, char** column_values, char** column_names)?
{?
? ? if (!column_names_printed) {?
? ? ? ? print_row(n_columns, column_names);?
? ? ? ? column_names_printed = 1;?
? ? }?
? ??
? ? print_row(n_columns, column_values);?
? ?
? ?return 0;?
}?
int main()?
{?
? ? sqlite3 *db=NULL;?
? ? char *errMsg = NULL;?
? ? int rc;?
? ??
? ? rc = sqlite3_open("shebei.db", &db);?
? ? if( rc ){?
? ? ? ? fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));?
? ? ? ? sqlite3_close(db);?
? ? ? ? exit(1);?
? ? }?
? ? else printf("open shebei.db successfully!\n");?
? ??
? ? column_names_printed = 0;?
? ? rc = sqlite3_exec(db, "SELECT shebei.* FROM shebei;", print_result, NULL, &errMsg);?
? ? column_names_printed = 1;?
? ? printf("\n");?
? ??
? ? printf("error code: %d\n", rc);?
? ? printf("error message: %s\n", errMsg);?
? ? sqlite3_close(db);?
? ? return 0;?
}?

注意如果如下的換行語句，

rc = sqlite3_exec(db, "CREATE TABLE students(number varchar(10), name varchar(10), \?
? ? ? ? ? ? ? ? ? ? ? ? ? ?sex varchar(6), age varchar(2));", NULL, NULL, NULL);
\之后如果有空格；則會出現；
Y:\dddd20\sqlitedemo1\demo1.cpp(39) : warning C4129: ' ' : unrecognized character escape sequence

刪除空格即可；

現在我們有sqlite3.dll跟一個sqlite3.def文件，并沒有用于VC++6.0的lib文件，可以利用sqlite3.def文件生成，步驟如下：?
? 1.將sqlite3.h（D:\sqlite-amalgamation-3_6_23.zip）拷貝到C:\Program Files\Microsoft Visual Studio\VC98\Include目錄下，這時編譯可通過，但鏈接錯誤，因為沒有LIB文件（）?
? 2.啟動一個命令行程序，進入VC的安裝目錄C:\Program Files\Microsoft Visual Studio\VC98\Bin，在這個目錄下面有一個LIB.exe文件，使用它就能生成sqlite3.lib文件，將sqlite3.def文件放到相同目錄，或者絕對路徑也可以，然后在命令行輸入如下命令：?
? ?LIB /MACHINE:IX86 /DEF:sqlite3.def?
? 該命令生成兩個文件：sqlite3.lib和sqlite3.exp?
? ?運行該命令時，如果提示找不到MSPDB60.DLL文件，可從其它目錄拷貝至Bin目錄下?
? 3.將生成的sqlite3.lib拷貝到Lib目錄下,將sqlite3.dll拷貝到C:\WINNT\system32目錄下?
? ?4.將sqlite3.lib加入到工程鏈接中，Project->Settings,Link選項卡，Object/library modules最后添入sqlite3.lib?

參閱：http://mxdxm.iteye.com/blog/634772

操作過程和完成結果如下圖；

把環境配置好；編譯運行程序；效果如下；

工程下載

sqlite相關下載，包括，h、Lib、dll文件;

http://pan.baidu.com/s/1slEEOMD

三 ADO訪問數據庫出現C2146、C2501

demodlg.h(25) : error C2146: syntax error : missing ';' before identifier 'm_pConnection'
demodlg.h(25) : error C2501: '_ConnectionPtr' : missing storage-class or type specifiers
demodlg.h(25) : error C2501: 'm_pConnection' : missing storage-class or type specifiers

在stdafx.h中加入如下語句再構建；

#import "c:\Program Files (x86)\common files\system\ado\msado15.dll"\
no_namespace\
rename("EOF", "adoEOF")

另外再看是否少了}；

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