ODBC C編程訪問數據庫

 新建一個Win32 Application，並在相應文件夾下新建一個book.mdb， 裏面有一個表BookInfo，表中有以下幾例：

id:

BookName:

Author:

等；

//------------------------------------------------------------------------------ // Copyright (c) 2009 eryar All rights reserved. // // File : Main.cpp // Author : [e-mail] // Date : 2009-11-8 16:09 // Version : 1.0v // // Description : ODBC編寫程序訪問數據庫的操作示例。 // //============================================================================== #include <windows.h> #include <sqlext.h> #include <odbcinst.h> #define IDM_FILE_OPEN 100001 #define IDM_FILE_EXIT 100002 #define IDM_HELP_CONTENT 200001 #define IDM_HELP_ABOUT 200002 #define IDM_DATA_CONNECT 300001 #define IDM_DATA_QUERY 300002 char* szAppName = "ODBC Demo"; HINSTANCE ghInst; HMENU WinMainMenu(HWND); LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { HWND hWnd; MSG Msg; WNDCLASS wndclass; char* szClassName = "CODBC"; ghInst = hInstance; wndclass.style = CS_HREDRAW|CS_VREDRAW; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.lpfnWndProc = WndProc; wndclass.hInstance = hInstance; wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH); wndclass.lpszMenuName = NULL; wndclass.lpszClassName = szClassName; if (!RegisterClass(&wndclass)) { MessageBox(NULL, "This program requires Windows NT! ", szAppName, MB_OK|MB_ICONERROR); return 0; } hWnd = CreateWindow(szClassName, szAppName, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL); ShowWindow(hWnd, nShowCmd); UpdateWindow(hWnd); while (GetMessage(&Msg, NULL, 0, 0)) { TranslateMessage(&Msg); DispatchMessage(&Msg); } return Msg.wParam; } LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam) { HDC hDC; PAINTSTRUCT ps; SQLRETURN retcode; SQLHENV henv; static SQLHDBC hdbc; SQLHSTMT hstmt; SQLINTEGER cbLength = 0; int iBookId = 0; char BookTitle[30]; switch(Msg) { case WM_CREATE: WinMainMenu(hWnd); return 0; case WM_SIZE: return 0; case WM_PAINT: hDC = BeginPaint(hWnd, &ps); EndPaint(hWnd, &ps); return 0; case WM_COMMAND: switch(wParam) { case IDM_FILE_OPEN: retcode = SQLConfigDataSource(hWnd, ODBC_ADD_SYS_DSN, "Microsoft Access Driver (*.mdb)", "" ); if (!retcode) { MessageBox(hWnd, "系統數據源配置錯誤！ ", szAppName, MB_OK|MB_ICONERROR); } return 0; case IDM_FILE_EXIT: PostQuitMessage(0); return 0; case IDM_DATA_CONNECT: retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv); if (retcode == SQL_SUCCESS) { retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); if (retcode == SQL_SUCCESS) { retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc); if (retcode == SQL_SUCCESS) { retcode = SQLConnect(hdbc, (SQLCHAR*)"book", SQL_NTS, (SQLCHAR*)"admin", SQL_NTS, (SQLCHAR*)" ", SQL_NTS); if (retcode == SQL_SUCCESS) { } else { MessageBox(hWnd, "SQLConnect : 數據庫連接失敗！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_DBC, hdbc); SQLFreeHandle(SQL_HANDLE_ENV, henv); } } else { MessageBox(hWnd, "SQLAllocHandle : SQL_HANDLE_DBC 連接句柄分配錯誤！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_DBC, hdbc); SQLFreeHandle(SQL_HANDLE_ENV, henv); } } else { MessageBox(hWnd, "SQLSetEnvAttr : 屬性設置錯誤！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_ENV, henv); } } else { MessageBox(hWnd, "SQLAllocHandle : SQL_HANDLE_ENV 環境變量分配錯誤！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_ENV, henv); } return 0; case IDM_DATA_QUERY: //char buffer[30]; retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt); if (retcode == SQL_SUCCESS) { SQLBindCol(hstmt, 1, SQL_C_CHAR, (SQLPOINTER)&BookTitle , sizeof(BookTitle), &cbLength ); retcode = SQLExecDirect(hstmt, (SQLCHAR*)"select BookName from BookInfo ", SQL_NTS); if (retcode == SQL_SUCCESS) { while( SQLFetch(hstmt) == SQL_SUCCESS) { MessageBox(hWnd, BookTitle, szAppName, MB_OK); } } else { MessageBox(hWnd, "SQLExecDirect : 數據庫操作錯誤！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_STMT, hstmt); } } else { MessageBox(hWnd, "SQLAllocHandle : SQL_HANDLE_STMT 語句變量分配錯誤！ ", szAppName, MB_OK|MB_ICONERROR); SQLFreeHandle(SQL_HANDLE_STMT, hstmt); } return 0; case IDM_HELP_CONTENT: MessageBox(hWnd, "help content ", szAppName, MB_OK); return 0; case IDM_HELP_ABOUT: MessageBox(hWnd, "help about ", szAppName, MB_OK); return 0; } return 0; case WM_SYSCOMMAND: switch(wParam) { case SC_CLOSE: if (MessageBox(hWnd, "Are you sure to quit? ", szAppName, MB_YESNOCANCEL|MB_ICONQUESTION) == IDYES) { PostQuitMessage(0); } return 0; default: return DefWindowProc(hWnd, Msg, wParam, lParam); } return 0; case WM_KEYDOWN: switch(wParam) { case VK_ESCAPE: PostQuitMessage(0); } return 0; case WM_DESTROY: PostQuitMessage(0); return 0; } return DefWindowProc(hWnd, Msg, wParam, lParam); } // WndProc /* */ HMENU WinMainMenu(HWND hWnd) { HMENU hMenu; HMENU hMenuPopup; hMenu = CreateMenu(); // File hMenuPopup = CreatePopupMenu(); AppendMenu(hMenuPopup, MF_STRING, IDM_FILE_OPEN, "&Open"); AppendMenu(hMenuPopup, MF_STRING, IDM_FILE_EXIT, "&Exit"); AppendMenu(hMenu, MF_POPUP, (UINT)hMenuPopup, "&File"); // Data hMenuPopup = CreatePopupMenu(); AppendMenu(hMenuPopup, MF_STRING, IDM_DATA_CONNECT, "&Connect"); AppendMenu(hMenuPopup, MF_STRING, IDM_DATA_QUERY, "&Query"); AppendMenu(hMenu, MF_POPUP, (UINT)hMenuPopup, "&Data"); // Help hMenuPopup = CreatePopupMenu(); AppendMenu(hMenuPopup, MF_STRING, IDM_HELP_CONTENT, "&Content"); AppendMenu(hMenuPopup, MF_STRING, IDM_HELP_ABOUT , "&About"); AppendMenu(hMenu, MF_POPUP, (UINT)hMenuPopup, "&Help"); SetMenu(hWnd, hMenu); return hMenu; } // WinMainMenu

 

1。編譯成功後，在File-》Open裏面的數據源名爲：Book

數據庫》選擇此文件夾下面的book.mdb；

 

2。 Data-》Connect， 連接數據庫；

 

3。 Data-》 Query， 查詢數據庫內容；