(I am using Delphi XE6 with ElevateDB unicode version.)

I pass in an object TMemObj which has various Properties. One of them is
Picture. This is a TStream. On the database it is a Blob field.

Procedure TServerMethods1.TableMemParams(
                const AObj   : TMemObj;
                var   AQuery : TEDBQuery);

begin
  WITH AQuery DO BEGIN
    { a number of Parameters then }

    if Assigned(AObj.Picture) then begin
      AObj.Picture.Position := 0;
      ParamByName('Param_Picture').AsStream := TMemoryStream.Create;
      ParamByName('Param_Picture').LoadFromStream(AObj.Picture,
ftBlob); {crashes here}
    end
    else
      ParamByName('Param_Picture').AsString := '';
  END;
end;

Out of curiosity I tried
ParamByName('Param_Picture').AsString := 'ABCDEF';

This line did place that string into the database!

So how do I the TStream from the Picture in the object into the Param?

I realise that this has been asked before but whatever I try I can't get
anything to work.

Regards,
  Peter Evans

Peter Evans wrote:

>      ParamByName('Param_Picture').AsStream := TMemoryStream.Create;

That's the problem I'd say. The field is responsible for it's own
management. I don't understand this line.

The rest should work, assuming of course that the parameter does exist
- otherwise it would return nil and you then call a function of it.

--

Matthew Jones

Peter

I'm with Matthew. I don't know what

>      ParamByName('Param_Picture').AsStream := TMemoryStream.Create;

is meant to do, or what it does to the table.


This is what I do - its a bit different because I'm loading a Word document in but the essence is the same.

 FileIn := TMemoryStream.Create;
 FileIn.LoadFromFile(LinkedDocsFrame1.Docs_File.AsString);
 FileIn.Position := 0;
 Contacts_LatestCV.LoadFromStream(FileIn);
 Contacts_LatestCVDate.AsDateTime := LinkedDocsFrame1.Docs_DateLinked.AsDateTime;
 FileIn.Free;


You could also treat your picture as a binary string and just use .AsString := 'X'+binary string

I think

Roy Lambert

Roy Lambert wrote:

> You could also treat your picture as a binary string and just use
> .AsString := 'X'+binary string

If Rudy were here you'd be shot! 8-)

But yes, I too have had binary data in a string (AnsiString for
byte-safety) and assigned it, but streams are a lot more reliable.

--

Matthew Jones

Matthew

>If Rudy were here you'd be shot! 8-)

I've already had one long discussion with Rudy on pointers. If he wants another one on improper use of strings I'm ready for it!

I do agree with your comments about use AnsiString though, or if you want to be a purist use an array of bytes (which to me translates into an ansistring

Roy

Peter,

I tend to use a TJPEGImage component, I think this is a standard Delphi component. It has an "Assign" method which seems to be capable of accepting most of the photo-file formats I throw at it.

The following usually works:

 aJPG:= TJpegImage.create;
 aJPG.Assign(AObj.Picture);
Query.ParamByName('Picture').Assign(aJPG);
Query.ExecSQL;
aJPG.Free;

It might even work without the intermediate step!

i.e.

Query.ParamByName('Picture').Assign(AObj.Picture);

If the images are not JPG format I am not sure what happens exactly. I think it usually copes. I know I have code which also uses a TBitmap in a similar way, which I can dig out if it is helpful.

Thanks to everyone's replies. I am still working on a solution. Will
respond in full then.
Regards,
  Peter Evans

> Thanks to everyone's replies. I am still working on a solution. Will

Thank you for all the replies.
It seems there was nothing wrong with ElevateDB and the way it stored
the Blob field. There was nothing wrong with the LoadFromStream either.

What was wrong was my understanding of how DataSnap moved data from the
client to and from the DataSnap server.

Things are working now.
Regards,
  Peter Evans