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Help with managing files in a database, using TADOTable and TDataSource.

Posted on 2004-09-08
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Last Modified: 2013-12-03
I'm using Delphi 7, and i am writing a mail client.
I need an example code, showing how to manage files in a MS Access Database, using those two components.
What do i need to use? May be an OLE Object?
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Question by:bbh2k3
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by:Wim ten Brink
ID: 12004989
How do you want to do that? What do you mean by managing files? If you want to store emails in your database, then store them in their raw format, which happens to be ANSI-text. Also, use a TADOQuery instead since it offers a better performance.
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by:geobul
ID: 12005010
Hi,

Perhaps you are talking about managing tables not files. If so, what kind of management you are interested in? Be more specific please.

Regards, Geo
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by:kretzschmar
ID: 12005228
nothing to append ...  waiting for further info
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by:EddieShipman
ID: 12010297
I would think he means file attachments and how to post them to an Access database blob field.
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Expert Comment

by:Wim ten Brink
ID: 12014466
Well, even file attachments are part of the raw email. They're just encoded as strings. All you need is a memo field... (Unless you're not retrieving emails in their raw format.)
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by:EddieShipman
ID: 12016217
Maybe he is decoding them and wants the capability to save the decoded file?

So bbh2k3, would you please enlighten us on your requirements?
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Author Comment

by:bbh2k3
ID: 12035547
I want to store the email as ANSI text, i want to know how to store the attachment in a blob field, and extract it later.
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geobul earned 500 total points
ID: 12038477
Hi,

The example below uses files from disk and a table with one OLE Object field named 'filebin'.

// adds one file to the table
procedure TForm1.btnSaveClick(Sender: TObject);
begin
  if OpenDialog1.Execute then begin
    with ADOTable1 do begin
      Open;
      Append;
      FieldByName('id').AsString := Edit1.Text; // id - string
      FieldByName('filename').AsString := OpenDialog1.Filename; // original filename - string
      TBlobFIeld(FieldByName('filebin')).LoadFromFile(OpenDialog1.Filename); // the content of the file
      Post;
      Close;
      ShowMessage('Done');
    end;
  end;
end;

// extracts the first file to disk
procedure TForm1.btnGetClick(Sender: TObject);
var
  s: string;
begin
  if SaveDialog1.Execute then begin
    s := Edit1.Text;
    with ADOTable1 do begin
      Open;
      First; // you'll have to replace this line with Locate or similar method for finding thhe record of interest
      TBlobFIeld(FieldByName('filebin')).SaveToFile(SaveDialog1.Filename);
      ShowMessage('Done');
      Close;
    end;
  end;
end;

The example doesn't contain errors handling at all.

Regards, Geo
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Expert Comment

by:geobul
ID: 12038516
If you also want to remove the file from the table use:

TBlobFIeld(ADOTable1.FieldByName('filebin')).Clear;

but in that case it would be necessary to check if that field is empty before saving it to a file this way:

if not ADOTable1.FieldByName('filebin').IsNull then ...

Hope this will help you.

Best regards, Geo
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