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Delete Record from MS Access using MFC

Posted on 2008-06-19
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Last Modified: 2013-11-20
Hi all,

I downloaded this project: http://www.codeproject.com/KB/database/readdb.aspx

and I can't seem to delete a record from this DB.

When i call Open on the recordset i get this exception:

"Dynamic cursors not supported by ODBC driver."

Help anyone?
// I added this function to the project:
 
void CReadDBDlg::OnDelete() 
{
		// TODO: Add your control notification handler code here
	CDatabase database;
	CString SqlString;
	CString sCatID, sCategory;
	CString sDriver = "MICROSOFT ACCESS DRIVER (*.mdb)";
	CString sDsn;
	CString sFile = "d:\\works\\ReadDB\\Test.mdb";
	// You must change above path if it's different
	int iRec = 0; 	
	
	// Build ODBC connection string
	sDsn.Format("ODBC;DRIVER={%s};DSN='';DBQ=%s",sDriver,sFile);
 
	// Open the database
	if(!database.Open(NULL,false,false,sDsn))
		return;
 
	CRecordset rsStudentSet(&database);
 
	TRY
	{
		
	// remove student from all the classes
    // the student is enrolled in
 
		if ( !database.BeginTrans( ) )
			return;
 
		
		CString SqlString =  "SELECT CatID, Category "
				"FROM Categories WHERE CatID = 22";
 
		if ( !rsStudentSet.Open(CRecordset::dynamic    , SqlString  , CRecordset::none) )
			return;
 
        while ( !rsStudentSet.IsEOF( ) )
        {
			CString sCatID,sCategory;
 
			rsStudentSet.GetFieldValue("CatID",sCatID);
			rsStudentSet.GetFieldValue("Category",sCategory);
 
 
			AfxMessageBox(sCatID + " - " + sCategory);
 
			if(rsStudentSet.CanUpdate())
			{
				rsStudentSet.Delete( );
				rsStudentSet.MoveNext( );
			}
        }
 
        database.CommitTrans( );
    }
 
    CATCH_ALL(e)
    {
        database.Rollback( );
        return;
    }
    END_CATCH_ALL
 
    rsStudentSet.Close( );
 
    return;
 
}

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Question by:kozmo_jonny
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12 Comments
 
LVL 49

Expert Comment

by:Gustav Brock
ID: 21823077
Well, did you try with Static?

But why ODBC with dotNet? Because that code is dated 2001?

Create a DataTableAdapter using the native driver for OLE db and a DataTable, then all the plumbing for CRUD (create, read, update, delete) is created automatically.

/gustav
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LVL 44

Expert Comment

by:AndyAinscow
ID: 21823095
CRecordset::dynamic
Isn't that telling it to use a dynamic cursor?  (See the error message).

Change that to another value (static cursor) and see if it works.



ps. There are a complete classes in MFC (CDaoRecordset...) specifically for using access databases in MFC.
0
 
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Author Comment

by:kozmo_jonny
ID: 21824139
i tried it with all open options. none work.
0
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LVL 49

Expert Comment

by:Gustav Brock
ID: 21824177
Are you running Visual Studio?

A bunch of examples and learning videos for reading/updating an Access table exist. None of these, I believe, use ODBC.

/gustav
0
 
LVL 2

Author Comment

by:kozmo_jonny
ID: 21824213
in my questions you can see my whole project.

http://www.codeproject.com/KB/database/readdb.aspx

i'm using VS6
0
 
LVL 44

Expert Comment

by:AndyAinscow
ID: 21824309
>>i tried it with all open options. none work.

Do you get other error messages?
0
 
LVL 49

Expert Comment

by:Gustav Brock
ID: 21824319
0
 
LVL 2

Author Comment

by:kozmo_jonny
ID: 21824408
I tried them all :-) none work my friend.

Option: rsStudentSet.Open(CRecordset::dynamic
Exception: {"Dynamic cursors not supported by ODBC driver."}

Option: rsStudentSet.Open(CRecordset::dynaset
Exception: {"ODBC driver does not support dynasets."}

Option: rsStudentSet.Open(CRecordset::snapshot
Exception: {"No columns were bound prior to calling SQLFetchScroll/SQLExtendedFetch"}

help me :'(
0
 
LVL 44

Expert Comment

by:AndyAinscow
ID: 21824451
?
As I said earlier - any reason you don't want to use the MFC classes specifically for access databases?
0
 
LVL 2

Author Comment

by:kozmo_jonny
ID: 21824488
no reason, it's the only sample project i found that uses MFC & MSACCESS.

I have a project in MFC (VS6) that I need to add MS ACCESS capabilities. so i started this as a small test case for me.

If you have another example that works i would love to see it.

10x
0
 
LVL 49

Expert Comment

by:Gustav Brock
ID: 21826285
I haven't worked with MFC but I noticed these samples - in C++ but might be helpful anyway:

http://msdn.microsoft.com/en-us/library/aa728901(VS.71).aspx

/gustav
0
 
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Accepted Solution

by:
AndyAinscow earned 500 total points
ID: 21828761
Look up CDaoDatabase, CDaoRecordset and other classes that begin with CDao in the help files.  There should be code snippets there.

There is at least one sample application and code that comes with VS6 that deals specifically with these classes.  (MFC and samples in the help file).
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