Tim

I'm doing a data conversion. During it I'm extracting stuff from a memo field in one table (sorted using HKStreams) into a TDBISAMTable and then streaming that table into a memo field in the new table. Works great for some but others I get the error above when trying to retrieve the data from the new table. Any ideas?

Roy Lambert

Tim


I've eliminated all of the records that don't have anything in the memo field and all those that stream properly (1742) and attached the remainder (232) where they don't.


Since I'm incapable of peering inside them can you have a shuftie and tell me what's going wrong.

TIA

Roy Lambert


function Smts(Fld: string; SrcTbl: TDBISAMDataset; DestTbl: TDBISAMTable): boolean;
var
 ms: TMemoryStream;
begin
 try
  DestTbl.Close;
  DestTbl.Exclusive := True;
  DestTbl.EmptyTable;
  DestTbl.Close;
  DestTbl.Exclusive := False;
  DestTbl.Open;
  if not SrcTbl.FieldByName(Fld).IsNull then begin
   ms := TMemoryStream.Create;
   try
    TMemoField(SrcTbl.FieldByName(Fld)).SaveToStream(ms);
    DestTbl.LoadFromStream(ms);
    DestTbl.Refresh;
    DestTbl.First;
   finally
    ms.Free;
   end;
  end;
  Result := True;
 except
  Result := False;
 end;
end;

Roy,

<< I've eliminated all of the records that don't have anything in the memo
field and all those that stream properly (1742) and attached the remainder
(232) where they don't. >>

I don't know what happened to those memo fields, but they appear to all have
3 bytes in them, which is less than what is required for a DBISAM table
stream header.  How were the memo fields populated ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim

>I don't know what happened to those memo fields, but they appear to all have
>3 bytes in them, which is less than what is required for a DBISAM table
>stream header. How were the memo fields populated ?

All 1974 records were populated the same way.

Were the 3 bytes the same in each case, if so what are they and I'll simply junk those on data transfer.


procedure TForm1.ObtainInLinePics;
var
Cntr: integer;
imgStream: TStringStream;
imgStr: string;
PicStream: TMemoryStream;
begin
InLinePics.First;
while not InLinePics.Eof do InLinePics.Delete;
ilMgr.ClearStreams;
imgStream := TStringStream.Create(imgStr);
if DoingEMails then imgStream.WriteString(impTbl.FieldByName('_InLine').AsString)
else if DoingHistory then imgStream.WriteString(Source.FieldByName('_InLine').AsString);
ilMgr.LoadFromStream(imgStream);
imgStream.Free;
if ilMgr.StreamList.Count > 0 then begin
 for Cntr := 0 to ilMgr.StreamList.Count - 1 do begin
  try
   with InLinePics do begin
    PicStream := TMemoryStream.Create;
    ilMgr.GetStream(ilMgr.StreamList[Cntr], PicStream);
    Insert;
    FieldByName('_Name').AsString := ilMgr.StreamList[Cntr];
    FieldByName('_CID').AsString := ilMgr.StreamList[Cntr];
    FieldByName('_Web').AsBoolean := False;
    FieldByName('_Size').AsInteger := PicStream.Size;
    TMemoField(FieldByName('_Item')).LoadFromStream(PicStream);
    Post;
    PicStream.Free;
   end;
  except
   if InLinePics.State in dsEditModes then InLinePics.Cancel;
  end;
 end;
end;
if InLinePics.RecordCount > 0 then begin
 if DoingEMails then begin
   InLinePics.First;
while not InLinePics.Eof do InLinePics.Delete;
 end else if DoingHistory then begin
  ReturnTableToMemo('_InLine', InLinePics, Source);
 end;
end else begin
 if DoingEMails then begin
  ClearField('_InLine', luMandN);
 end else if DoingHistory then begin
  ClearField('_InLine', Source);
 end;
end;
end;


procedure TForm1.ClearField(Fld: string; DestTbl: TDBISAMTable);
var
WasEditing: boolean;
begin
WasEditing := (DestTbl.State in dsEditModes);
if not WasEditing then GetRecordLock(DestTbl, 200);
DestTbl.FieldByName(Fld).AsString := 'x*x';
if not WasEditing then DestTbl.Post;
end;

Roy,

<< Were the 3 bytes the same in each case, if so what are they and I'll
simply junk those on data transfer. >>

I didn't look that closely, but what the 3 bytes are is probably irrelevant
anyways.

In your code, what does the GetStream function or procedure look like ?  My
guess is that there's an issue in there somewhere.  DBISAM will never save
just 3 bytes as a table stream - the signature alone is 16 bytes.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim


>In your code, what does the GetStream function or procedure look like ? My
>guess is that there's an issue in there somewhere. DBISAM will never save
>just 3 bytes as a table stream - the signature alone is 16 bytes.


procedure THKStreams.GetStream(const ID: string; Dest: TStream);
var i: integer;
begin
if (length(id) > 0) then begin
 i := Streamlist.IndexOf(ID);
 if i >= 0 then
  dest.CopyFrom(TMemoryStream(Streamlist.objects[i]), 0);
 dest.Position := 0;
end;
end;

But even if that is a problem I'm using this component to populate a TDBISAMTable which is the stuffed into a memo field with

procedure ReturnTableToMemo(Fld: string; SrcTbl, DestTbl: TDBISAMTable);
var
ms: TMemoryStream;
WasEditing: boolean;
begin
ms := TMemoryStream.Create;
try
 SrcTbl.SaveToStream(ms);
 WasEditing := (DestTbl.State in dsEditModes);
 if not WasEditing then GetRecordLock(DestTbl, 200);
 if SrcTbl.RecordCount > 0
  then TMemoField(DestTbl.FieldByName(Fld)).LoadFromStream(ms)
 else DestTbl.FieldByName(Fld).Clear;
 if not WasEditing then DestTbl.Post;
finally
 ms.Free;
end;
end;

So wouldn't it be here where the problem arose? If it was in the earlier code the table shouldn't have been populated.

Roy Lambert

Tim


It was actually me. I'd forgotten to "clean up" the column after processing.


Roy Lambert

Roy,

<< It was actually me. I'd forgotten to "clean up" the column after
processing.  >>

Well, that makes it:

Tim   -   1
Roy  -   43



--
Tim Young
Elevate Software
www.elevatesoft.com

Roy,

Just to clarify - what I was poking fun at was me.  Usually the problems you
bring up are my fault, not yours, but it was hard to say that for sure from
my post.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim


There is NO need to clarify those type of jokes - I enjoy them regardless of who they're aimed at. And anyway I'd suggest more like

Tim   -   27
Roy  -   34


Roy Lambert