HOWTO: Use Dynasets with Microsoft SQL Server Version 6.x

Last reviewed: July 31, 1997
Article ID: Q136994

The information in this article applies to:

The Microsoft Foundation Classes (MFC) included with: - Microsoft Visual C++, 16-bit Edition, versions 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 2.0, 2.1, 2.2, 4.0,
```
     4.1, 4.2, 5.0
```

SUMMARY

Microsoft SQL Server versions 6.0 and 6.5 support dynasets. To use an updatable dynaset, you must have a unique index on one or more fields in the table. If there is no such index, the recordset will be read only. Also, CRecordset::CanAppend() and CRecordset::CanUpdate() will return FALSE.

MORE INFORMATION

If you create a dynaset without specifying a unique index on one or more fields in the table and then try to update or add a record, MFC will throw an exception that says the cursor is read-only. Additionally, you will see the following errors in the MFC Trace output:

In Visual C++ version 1.5x:

   Cursor is read-only
   State:S1009[Microsoft][ODBC SQL Server Driver][SQL Server]

   Warning: 0 rows affected by update operation (expected 1).
   No rows were affected by the update or delete operation.

In Visual C++ version 2.x and 4.x:

   Error: failure updating record.
   Cursor is read-only
   State:S1009,Native:16929,Origin:[Microsoft][ODBC SQL Server Driver]
         [SQL Server]

In Visual C++ 5.0, you will see:

   Cursor concurrency changed
   State:01S02, Native:0, Origin: [Microsoft][ODBC SQL Server Driver]

   Warning: Concurrency changed by the driver.
   Marking CRecordset as not updatable.
   Recordset is read-only.

Note that if you use the PRIMARY KEY specification new to SQL Server version 6.0 when creating your tables, you will automatically generate a unique index on the primary key. Here is an example of this syntax:

      CREATE TABLE Table1
         (cola CHAR(8) PRIMARY KEY NOT NULL,
         colb CHAR(8))

If you are using the Microsoft SQL Server ODBC driver, version 2.65.0201, that comes with SQL Server version 6.5, MFC will throw an exception that says:

  "Invalid argument value"

Additionally, you will see the following errors in the MFC Trace output:

   Error: failure updating record.
   Invalid argument value
   State:S1009,Native:0,Origin:[Microsoft][ODBC SQL Server Driver]

Additional query words: CanUpdate CanAppend
Keywords : MfcDatabase kbusage kbhowto
Technology : kbMfc
Version : 1.51 1.52 2.0 2.1 2.2 4.0 5.0
Platform : NT WINDOWS
Issue type : kbhowto

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Last reviewed: July 31, 1997
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