PRB: ODBC Error When Using CRecordset Without Deriving From It (155848)
The information in this article applies to:
- The Microsoft Foundation Classes (MFC), when used with:
- Microsoft Visual C++, 32-bit Enterprise Edition 4.2
- Microsoft Visual C++, 32-bit Professional Edition 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition 5.0
- Microsoft Visual C++, 32-bit Professional Edition 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition 6.0
- Microsoft Visual C++, 32-bit Professional Edition 6.0
- Microsoft Visual C++, 32-bit Learning Edition 6.0
This article was previously published under Q155848 SYMPTOMS
With Visual C++ 4.2 and later, you can use the CRecordset class without
deriving from it, allowing you to open a read-only recordset on any data
source. This may be helpful if you are using CRecordset::GetFieldValue(),
for example. However, when calling Open() for the CRecordset object, you
may see a message box with the following message in it:
No columns were bound prior to calling SQLExtendedFetch
CAUSE
The CDatabase object used by the CRecordset object loaded the ODBC cursor
library. The cursor library requires that there be at least one bound
column for a recordset. The Visual C++ documentation doesn't make this
requirement clear.
RESOLUTION
Do not load the cursor library by specifying FALSE for the last argument of
CDatabase::Open(). For example:
CDatabase db;
db.Open("MyDataSource", FALSE, FALSE, "ODBC;", FALSE);
CRecordset rs( &db );
rs.Open(...);
...
If your driver does not support dynasets, then the cursor library is
required and you will not be able to use the CRecordset class without
deriving from it.
STATUS
Microsoft has confirmed this to be a problem with the Visual C++ 4.2
documentation. The Visual C++ 5.0 documentation has been changed to reflect
this information and states:
Note if you declare a recordset object without deriving from
CRecordset, do not have the ODBC Cursor Library loaded. The cursor
library requires that the recordset have at least one bound column;
however, when you use CRecordset directly, none of the columns are
bound. The member functions CDatabase::OpenEx and CDatabase::Open
control whether the cursor library will be loaded."
| Modification Type: | Major | Last Reviewed: | 12/8/2003 |
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| Keywords: | kbDatabase kbdocfix kbMDACNoSweep kbprb kbProgramming kbusage KB155848 |
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