C / C++ / MFC

13-Aug-01 8:17

Hello.

This portion of code works perfect in an aplication that conect to Access 2000 with a DSN ODBC.

CRecordset rs;
rs.Open(CRecordset::forwardOnly,"SELECT COUNT(*) FROM mytable",CRecordset::readOnly);
short nField=0;
CString str;
rs.GetFieldValue(nField,str);
long NumRecords = atol(LPCSTR(str));

Now I am porting the aplication to works with SQL Server 2000 and this portion of code give me the error: "State:S1002,Native Blush | :O

,Origin:[Microsoft][ODBC SQL Server Driver] Invalid column number".

In MSDN I have found "GetFieldValue calls the ODBC API function SQLGetData. If your driver outputs the value SQL_NO_TOTAL for the actual length of the field value, GetFieldValue throws an exception. For more information about SQLGetData, see the ODBC SDK Programmer's Reference"

I don't know if this is the problem. Anybody can tell me how can I solve this problem?.

Thanks in advance.

Tomás.

Bret Faller13-Aug-01 8:33

13-Aug-01 8:33

SQL automatically makes column 0 the bookmark column (which is useless unless you're using bookmarks). Start your column numbers at 1.

Bret Faller
Odyssey Computing, Inc.

Tomas13-Aug-01 8:54

13-Aug-01 8:54

Thank you Bret.

This is not the solution.

I start with 1 and the error is "The index is not valid or the field name is incorrect".

I think the problem is another but I have no idea.

Tomás

Bret Faller13-Aug-01 9:02

13-Aug-01 9:02

Are you using a snapshot or dynaset recordset?

Bret Faller
Odyssey Computing, Inc.

Tomas13-Aug-01 9:20

13-Aug-01 9:20

I am using...

In the constructor:
m_nDefaultType = dynaset;

And to open:
rs.Open(CRecordset::forwardOnly,_T("SELECT COUNT(*) FROM mytable"),CRecordset::readOnly);

Bret Faller13-Aug-01 11:04

13-Aug-01 11:04

Actually, the anonymous guy is correct. You should use GetRecordCount(). And I believe the reason the other doesn't work is because I think the GetFieldValue gets a column value rather than a returned recordset value. So just do a plain open with a NULL query in order to get the whole recordset then do a GetRecordCount.

Bret Faller
Odyssey Computing, Inc.

13-Aug-01 9:56

Seems like you just want the number of records in the database, so why don't you use the CRecordset::GetRecordCount() function.
Confused | :confused:

Tomas13-Aug-01 12:01

13-Aug-01 12:01

Yes this is a solution, but too slowly because you need to check all the recordset to know the number of records.

MoveFirst();
DoWhile(IsBof()) {
MoveNext();
count++;
}

Is more eficient to do a SELECT COUNT(*) rather a DoWhile().

Tomás

What does this function do?

14-Aug-01 12:27

No. You don't check it like this.

For example:

let's say you have a class CMyRecordset derived from CRecordset, and you use the default SQL, once you open the your RS class all you have to do is this..

CMyRecordset rs(db);
long lNumOfRecords;
rs.Open();
// if opens without any problem..
// this should give you the number of records you are looking for..
lNumOfRecords = rs.GetRecordCount();

Confused | :confused:

Bret Faller13-Aug-01 8:13

Re: What does this function do?

13-Aug-01 8:13

Good day,

Does anyone know what exactly GetSuperWndProc() does? I keep getting this as an unresolved external in my embeddedVC program even though I never call it. If I override it it will compile fine but crashes on execution. I was wondering if anyone knows what its supposed to do so that I can implement it. Thanks.

Bret Faller
Odyssey Computing, Inc.

Anders Molin13-Aug-01 8:42

Anders Molin

13-Aug-01 8:42

Are you using any thirdparty libraries?

I don't think it a standard API function. I have never seen it before, and a search on all of MSDN don't get anything...

- Anders

Money talks, but all mine ever says is "Goodbye!"

Re: What does this function do?

Bret Faller13-Aug-01 8:44