Problem with write binary data to OLE field in Access

[lialie]

Hi~

I would like to save images in OLE field in Microsoft Access. It writes
the binary data which read from an JPEG/BMP file.
But seems I meet an encoding problem.
The following code demos that.
Any sugguestion?

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import win32com.client as wc

conn = wc.Dispatch(r'A DODB.Connection ')
recordset = wc.Dispatch(r'A DODB.RecordSet' )

dsn = 'Provider=Micro soft.Jet.OLEDB. 4.0;Data Source="test.md b";'
conn.Open(dsn)
print conn

k = recordset.Open( '[tblImageDataTyp es]', conn, 1, 3)

#recordset.AddN ew()
#recordset.Fiel ds('Field3_GENE RAL').AppendChu nk(open('tt.jpg ', 'rb').read())
#recordset.Upda te()
#print ">>Actual Size: ", recordset.Field s('Field3_GENER AL').ActualSize

recordset.MoveF irst()
kk = recordset.Field s('Field3_GENER AL').GetChunk(
recordset.Field s('Field3_GENER AL').ActualSize )
print len(str(kk).dec ode('utf-16'))
print len(open('tt.jp g', 'rb').read())

recordset.Close
conn.Close()
############### ############### #
One of the results:
the length of original file is : 2598
the actual size of the field is: 3658
the length decode from the chunk is: 1829

I try to write some text files into the filed and read it out, it is OK.
Windows XP sp2; Python 2.4.4; Pywin32 210; Microsoft Access 2002
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Regards,
lialie