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SQL Server 2008 R2 (10.50.x) Native Client or earlier

SQL Server Native Client ODBC Driver version , (SQLPOINTER*) 0x1, 0, &iSize) // Attempting to determine storage size needed Query: select convert(varchar(36), '123') SQLGetData(hstmt, SQL_WCHAR. This application queries a varchar column and binding as Unicode (SQL_UNICODE/SQL_WCHAR): The following shows the impact of the driver change when you use the incorrect pattern. Using SQLGetData to get the size of data is not unsupported. SQLGetData can only be called to retrieve chunks of actual data. , (SQLPOINTER*)pBuffer, iSize, &iSize) // Retrieve data , (SQLPOINTER*)0x1, 0, &iSize) // Get storage size needed The following pattern should not be used: // bad However, SQLGetData should not be used in this scenario. GetMyFavoriteAPI(pBuffer, &iSize) // Retrieve actual data GetMyFavoriteAPI(pBuffer, &iSize) // Returns needed size in iSize The following pattern is common for Windows programmers: int iSize = 0 Many Windows functions let you specify a buffer size of 0 and the returned length is the size of the returned data. Prior versions of the SQL Server Native Client ODBC driver returned a length value, which can be incorrect.

ODBC functions, such as SQLGetData, SQLBindCol, SQLBindParameter, return (-4) SQL_NO_TOTAL as the length/indicator parameter when using the SQL Server 2012 Native Client ODBC driver. The SQL Server 2012 (11.x) Native Client ODBC Driver (SQLNCLI11.dll) changed how it does of SQL_WCHAR* (NCHAR/NVARCHAR/NVARCHAR(MAX)) and SQL_CHAR* (CHAR/VARCHAR/NARCHAR(MAX)) conversions. Switch to the new Microsoft OLE DB Driver (MSOLEDBSQL) for SQL Server or the latest Microsoft ODBC Driver for SQL Server going forward. The SQL Server Native Client (SQLNCLI or SQLNCLI11) and the legacy Microsoft OLE DB Provider for SQL Server (SQLOLEDB) are not recommended for new development. The SQL Server Native Client (often abbreviated SNAC) has been removed from SQL Server 2022 (16.x) and SQL Server Management Studio 19 (SSMS).