CRecordset.Close() causes exception

Hi,
I'm having problems with VC++ 6.0 reading an Access 2000 database.
CRecordset::Close() throws an exception. I've created a simple test
dialog which does an open and close of a CRecordset. The database has
one table called 'Addresses' in it. The CAddressSet was created by the
Class Wizard.
void CDatabaseDlg::OnOK()
{
CDatabase db;
db.Open(NULL,FALSE,FALSE,"DSN=c:\\dev\\db1.mdb");
// Construct the snapshot object
CAddressSet rsAddr( NULL );
// Set options if desired, then open the recordset
rsAddr.Open(CRecordset::snapshot, NULL, CRecordset::none );
rsAddr.Close( );
db.Close( );
Dialog::OnOK();
}
The Close method throws on the AFX_SQP_SERVER line below:
RETCODE nRetCode;
if (m_hstmt != SQL_NULL_HSTMT)
{
AFX_SQL_SYNC(::SQLFreeStmt(m_hstmt, SQL_DROP));
m_hstmt = SQL_NULL_HSTMT;
}
This program just couldn't get any simpler - and yet it doesn't work!
Anybody got any clue as to why?
Many thanks,
Jeremy
Recordset is not connected to database? Recordset is completely empty?
etc?
Free software - Baxter Codeworks www.baxcode.com
"Jezzer" <Jemtaylor@.yahoo.com> wrote in message
news:1115894836.839503.104060@.g14g2000cwa.googlegr oups.com...
> Hi,
> I'm having problems with VC++ 6.0 reading an Access 2000 database.
> CRecordset::Close() throws an exception. I've created a simple test
> dialog which does an open and close of a CRecordset. The database has
> one table called 'Addresses' in it. The CAddressSet was created by the
> Class Wizard.
> void CDatabaseDlg::OnOK()
> {
> CDatabase db;
> db.Open(NULL,FALSE,FALSE,"DSN=c:\\dev\\db1.mdb");
> // Construct the snapshot object
> CAddressSet rsAddr( NULL );
> // Set options if desired, then open the recordset
> rsAddr.Open(CRecordset::snapshot, NULL, CRecordset::none );
>
> rsAddr.Close( );
> db.Close( );
>
> Dialog::OnOK();
> }
> The Close method throws on the AFX_SQP_SERVER line below:
> RETCODE nRetCode;
> if (m_hstmt != SQL_NULL_HSTMT)
> {
> AFX_SQL_SYNC(::SQLFreeStmt(m_hstmt, SQL_DROP));
> m_hstmt = SQL_NULL_HSTMT;
> }
> This program just couldn't get any simpler - and yet it doesn't work!
> Anybody got any clue as to why?
> Many thanks,
> Jeremy
>
|||Yes, I see why it might look like that with the NULL in the CRecordSet
declaration. I've defined my test database using ODBC manager and the
GetDefaultConnect() method looks like this:
CString CAddressSet::GetDefaultConnect()
{
return _T("ODBC;DSN=db1");
}
where 'db1' is my database with the Addresses table in it. This was all
put there by the wizard.
I have had this same test retrieving the data succesfully but I took
that stuff out to make the example less cluttered.
It's just the Close that crashes whether you retrieve stuff or not.
cheers anyway...
Jeremy
|||Hi all,
I've made some progress with this problem now. I've discovered that
CRecordSet::Close() only crashes when running under Visual Studio -
when the exe is run stand-alone it works fine. I can remove the 'fudge'
and it loads the DB Ok.
The 'fudge' I use where I set m_hstmnt = SQL_NULL_HSTMT in the
::Close() method means that when debugging the method does not crash -
but it seems to cause the Access interface to run *extremely* slowly.
No CPU being used - just seems to be waiting an awful lot. So I suspect
that whatever is being freed by the 'SQLFreeStmt' call is getting
clogged. My hunch is that Access or ODBC is waiting for a space in some
buffer to open up and eventually decides to remove the oldest 'thing' -
whatever that is.
A search of Google Groups shows that lots of people have had this
problem - is there nobody out there that knows the answer?
cheers
Jeremy

CRecordset.Close() causes exception

Hi,
I'm having problems with VC++ 6.0 reading an Access 2000 database.
CRecordset::Close() throws an exception. I've created a simple test
dialog which does an open and close of a CRecordset. The database has
one table called 'Addresses' in it. The CAddressSet was created by the
Class Wizard.
void CDatabaseDlg::OnOK()
{
CDatabase db;
db.Open(NULL,FALSE,FALSE,"DSN=c:\\dev\\db1.mdb");
// Construct the snapshot object
CAddressSet rsAddr( NULL );
// Set options if desired, then open the recordset
rsAddr.Open(CRecordset::snapshot, NULL, CRecordset::none );
rsAddr.Close( );
db.Close( );
Dialog::OnOK();
}
The Close method throws on the AFX_SQP_SERVER line below:
RETCODE nRetCode;
if (m_hstmt != SQL_NULL_HSTMT)
{
AFX_SQL_SYNC(::SQLFreeStmt(m_hstmt, SQL_DROP));
m_hstmt = SQL_NULL_HSTMT;
}
This program just couldn't get any simpler - and yet it doesn't work!
Anybody got any clue as to why'
Many thanks,
JeremyRecordset is not connected to database? Recordset is completely empty?
etc?
----
Free software - Baxter Codeworks www.baxcode.com
----
"Jezzer" <Jemtaylor@.yahoo.com> wrote in message
news:1115894836.839503.104060@.g14g2000cwa.googlegroups.com...
> Hi,
> I'm having problems with VC++ 6.0 reading an Access 2000 database.
> CRecordset::Close() throws an exception. I've created a simple test
> dialog which does an open and close of a CRecordset. The database has
> one table called 'Addresses' in it. The CAddressSet was created by the
> Class Wizard.
> void CDatabaseDlg::OnOK()
> {
> CDatabase db;
> db.Open(NULL,FALSE,FALSE,"DSN=c:\\dev\\db1.mdb");
> // Construct the snapshot object
> CAddressSet rsAddr( NULL );
> // Set options if desired, then open the recordset
> rsAddr.Open(CRecordset::snapshot, NULL, CRecordset::none );
>
> rsAddr.Close( );
> db.Close( );
>
> Dialog::OnOK();
> }
> The Close method throws on the AFX_SQP_SERVER line below:
> RETCODE nRetCode;
> if (m_hstmt != SQL_NULL_HSTMT)
> {
> AFX_SQL_SYNC(::SQLFreeStmt(m_hstmt, SQL_DROP));
> m_hstmt = SQL_NULL_HSTMT;
> }
> This program just couldn't get any simpler - and yet it doesn't work!
> Anybody got any clue as to why'
> Many thanks,
> Jeremy
>|||Yes, I see why it might look like that with the NULL in the CRecordSet
declaration. I've defined my test database using ODBC manager and the
GetDefaultConnect() method looks like this:
CString CAddressSet::GetDefaultConnect()
{
return _T("ODBC;DSN=db1");
}
where 'db1' is my database with the Addresses table in it. This was all
put there by the wizard.
I have had this same test retrieving the data succesfully but I took
that stuff out to make the example less cluttered.
It's just the Close that crashes whether you retrieve stuff or not.
cheers anyway...
Jeremy|||Hi all,
I've made some progress with this problem now. I've discovered that
CRecordSet::Close() only crashes when running under Visual Studio -
when the exe is run stand-alone it works fine. I can remove the 'fudge'
and it loads the DB Ok.
The 'fudge' I use where I set m_hstmnt = SQL_NULL_HSTMT in the
::Close() method means that when debugging the method does not crash -
but it seems to cause the Access interface to run *extremely* slowly.
No CPU being used - just seems to be waiting an awful lot. So I suspect
that whatever is being freed by the 'SQLFreeStmt' call is getting
clogged. My hunch is that Access or ODBC is waiting for a space in some
buffer to open up and eventually decides to remove the oldest 'thing' -
whatever that is.
A search of Google Groups shows that lots of people have had this
problem - is there nobody out there that knows the answer?
cheers
Jeremy