BUG: SQLGetData Returns SQL_SUCCESS on a Binary Column

ID: Q124321

The information in this article applies to:

Microsoft Open Database Connectivity, version 2.0

BUG# QJET: 1780 (2.002317)

SYMPTOMS

Under certain conditions when SQLGetData is called on a binary column more than once, it may return SQL_SUCCESS when it should return SQL_NO_DATA_FOUND. This happens only for binary, varbinary, or longbinary type of columns.

For example, consider the following sequence of calls which demonstrate the problem:


   SQLAllocEnv(phenv)
   SQLAllocConnect(henv,phdbc)
   SQLConnect(szDSN,cbDSN,szUID,cbUID,szAuthStr,cbAuthStr)

   SQLAllocStmt(hdbc,phstmt)
   SQLExecDirect(hstmt,"Create table test (col1 longbinary)",SQL_NTS)
   SQLExecDirect(hstmt,"Insert into test values('abc')",SQL_NTS)
   SQLExecDirect(hstmt,"Insert into test values('abcd')",SQL_NTS)
   SQLFreeStmt(hstmt,SQL_CLOSE)

   SQLSetStmtOption(hstmt,SQL_CURSOR_TYPE, SQL_CURSOR_KEYSET_DRIVEN)
   SQLSetStmtOption(hstmt,SQL_ROWSET_SIZE,2)

   SQLExecDirect(hstmt,"Select * from test",SQL_NTS)
   SQLBindCol(hstmt,1,SQL_C_BINARY,rgbValue,cbValueMax,pcbValue)
   SQLExtendedFetch(hstmt,SQL_FETCH_FIRST,1,pcrow,rgfRowStatus)

   SQLGetData(hstmt,1,SQL_C_CHAR,cbValueMax,pcbValue)

This returns SQL_SUCCESS with *rgbValue="616263" and *pcbValue=6. But calling SQLGetData second time on the same column like:


   SQLGetData(hstmt,1,SQL_C_CHAR,VALID,100,VALID)

Returns SQL_SUCCESS with *rgbValue="" and *pcbValue=0

This should return SQL_NO_DATA_FOUND.

The behavior occurs only if the following conditions apply:

The column type is either binary, longbinary, or Varbinary and is bound.

The data in the second row is longer than first row.

A SQLExtendedFetch with fFetchType as SQL_FETCH_FIRST and SQLGetData immediately following the SQLExtendedFetch call.

STATUS

Microsoft has confirmed this to be a problem in ODBC Access Driver version 2.00.2317. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

Additional query words: 2.00.2317 ODBC VISUAL C++ MSVC MFC Windows NT

Keywords :
Version : WINDOWS:2.0
Platform : WINDOWS
Issue type :