NOTE: For information about how to create .MDB files programmatically using
Visual C++ version 4.x or later, please see the following article in the
Microsoft Knowledge Base:
INFO: Accessing CREATE_DB, REPAIR_DB, and COMPACT_DB
An .mdb file is always required to configure a Microsoft Access data source
either by using the Open Database Connectivity (ODBC) administrator or by
configuring the data source programmatically. An .mdb file cannot be
created by using the MFC Database Classes or the ODBC application
programming interface (API).
You can use one of the following methods to have an application configure a
data source on your computer:
- Ship and install the .mdb file along with the application.
- Make the .mdb file into a user-defined resource. Then, copy the .mdb
file at run time.
This article discusses the second method, making the .mdb file into a user-
You can use a user-defined resource to attach miscellaneous data to a .EXE
file. If an .mdb file is made into a resource, the resource can be loaded
at run time and then written to an .mdb file. The steps required to do this
are as follows:
- Create an .mdb file either by using Microsoft Access or MSQuery.
- Create the .mdb file as a user-defined resource by adding the following
line to your .RC file:
mdb_file MDB_RESOURCE filename.mdb
mdb_file is a name for identifying the resource.
MDB_RESOURCE is a name for identifying the type of the resource
and can be any user-defined type.
filename.mdb is the name of the .mdb file.
- Load the resource and write it out to an .mdb file. You can use the
following function, from anywhere in your application, to create the
.mdb file. (A typical place for creating the .mdb file would be the
override of the CWinApp::InitInstance() function.)
// Get the instance handle - required for loading the resource
HINSTANCE hInst = AfxGetInstanceHandle();
// Load the user-defined resource.
HRSRC hmdbFile = ::FindResource(hInst, "mdb_file", "MDB_RESOURCE");
HGLOBAL hRes = ::LoadResource(hInst, hmdbFile);
DWORD dwResSize = ::SizeofResource(hInst, hmdbFile);
if (hRes != NULL)
UINT FAR* lpnRes = (UINT FAR*)::LockResource(hRes);
CString szFileName = "Filename.mdb";
// Create the .mdb file
CFile f( szFileName, CFile::modeCreate | CFile::modeWrite );
// Write the user-defined resource to the .mdb file
CATCH( CFileException, e )
afxDump << "File could not be opened " << e->m_cause << "\n";
#ifndef WIN32 //Unlock Resource is obsolete in the Win32 API
The one disadvantage of this method is that it increases the size of the
.exe file according to the size of the .mdb file. Because even an empty
.mdb file is 64K in size, the .exe is increased by at least 64K. One way to
reduce the size of the .exe is to store a compressed .mdb file onto the
.exe and expand it at run time when storing the resource.
For more information on user-defined resources, refer to the Windows SDK
For additional information on configuring a data source programmatically,
please see the following articles in the Microsoft Knowledge Base:
How To Configure ODBC Data Sources on the Fly
How To Create Tables with Foundation Database Classes
Article ID: 118609 - Last Review: November 21, 2006 - Revision: 3.2
- Microsoft Foundation Class Library 4.2, when used with:
- Microsoft Visual C++ 1.5 Professional Edition
- Microsoft Visual C++ 1.51
- Microsoft Visual C++ 1.52 Professional Edition
- Microsoft Visual C++ 2.0 Professional Edition
- Microsoft Visual C++ 2.1
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This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.