AppendChunk Method

See Also      Applies To

Appends data from a string expression to a Memo or Long Binary CdbField object in a CdbRecordset.

Syntax

VOIDAppendChunk(LPVARIANT pv );

Parameters

Remarks

You can use the AppendChunk and GetChunk methods to access subsets of data in a Memo or Long Binary field.

You can also use these methods to conserve string space when you work with Memo and Long Binary fields. Certain operations (copying, for example) involve temporary strings. If string space is limited, you may need to work with chunks of a field instead of the entire field.

If there is no current record when you use AppendChunk, an error occurs.

Notes

• The initial AppendChunk operation (after an Edit or AddNew call) will simply place the data in the field, overwriting any existing data. Subsequent AppendChunk calls within the same Edit or AddNew session will then add to the existing data.
  
  
• In an ODBCDirect workspace, unless you first edit another field in the current record, using AppendChunk will fail (though no error occurs) while you are in Edit mode.
  
  
• In an ODBCDirect workspace, after you use AppendChunk on a field, you cannot read or write that field in an assignment statement until you move off the current record and then return to it. You can do this by using the MoveNext and MovePrevious methods.

Usage

#include <afxole.h>
#include <dbdao.h>

CdbRecordset      rs;
CdbField         fld;
COleVariant      vVal("abcdefghijklmnop", VT_BSTRT);
...                     // Initialize recordset, etc.
fld = rs.Fields[0];         // Get a field.
fld.AppendChunk(&vVal);    // Append the chunk.