How do I know which database format a file (or a set of files) was created with &…

存储架构 2017-12-31

I have a number of data files created by many different programs. Is there a way to determine the database and version of the database that was used to create the data file.

For example, I'd like to identify which files are created from Microsoft Access, dBASE, FileMaker, FoxPro, SQLite or others.

I really just want to somehow quickly scan the files, and display information about them, including source Database and Version.

For reference, I'm using Delphi 2009.

First of all, check the file extension. Take a look at the corresponding wikipedia article
, or other sites.

Then you can guess the file format from its so called "signature".

This is mostly the first characters content, which is able to identify the file format.

You've an updated list at this very nice Gary Kessler's
website.

For instance, here is how our framework identify the MIME format from the file content
, on the server side:

function GetMimeContentType(Content: Pointer; Len: integer;
  const FileName: TFileName=''): RawUTF8;
begin // see http://www.garykessler.net/library/file_sigs.html for magic numbers
  result := '';
  if (Contentnil) and (Len>4) then
    case PCardinal(Content)^ of
    $04034B50: Result := 'application/zip'; // 50 4B 03 04
    $46445025: Result := 'application/pdf'; //  25 50 44 46 2D 31 2E
    $21726152: Result := 'application/x-rar-compressed'; // 52 61 72 21 1A 07 00
    $AFBC7A37: Result := 'application/x-7z-compressed';  // 37 7A BC AF 27 1C
    $75B22630: Result := 'audio/x-ms-wma'; // 30 26 B2 75 8E 66
    $9AC6CDD7: Result := 'video/x-ms-wmv'; // D7 CD C6 9A 00 00
    $474E5089: Result := 'image/png'; // 89 50 4E 47 0D 0A 1A 0A
    $38464947: Result := 'image/gif'; // 47 49 46 38
    $002A4949, $2A004D4D, $2B004D4D:
      Result := 'image/tiff'; // 49 49 2A 00 or 4D 4D 00 2A or 4D 4D 00 2B
    $E011CFD0: // Microsoft Office applications D0 CF 11 E0 = DOCFILE
      if Len>600 then
      case PWordArray(Content)^[256] of // at offset 512
        $A5EC: Result := 'application/msword'; // EC A5 C1 00
        $FFFD: // FD FF FF
          case PByteArray(Content)^[516] of
            $0E,$1C,$43: Result := 'application/vnd.ms-powerpoint';
            $10,$1F,$20,$22,$23,$28,$29: Result := 'application/vnd.ms-excel';
          end;
      end;
    else
      case PCardinal(Content)^ and $00ffffff of
        $685A42: Result := 'application/bzip2'; // 42 5A 68
        $088B1F: Result := 'application/gzip'; // 1F 8B 08
        $492049: Result := 'image/tiff'; // 49 20 49
        $FFD8FF: Result := 'image/jpeg'; // FF D8 FF DB/E0/E1/E2/E3/E8
        else
          case PWord(Content)^ of
            $4D42: Result := 'image/bmp'; // 42 4D
          end;
      end;
    end;
  if (Result='') and (FileName'') then begin
    case GetFileNameExtIndex(FileName,'png,gif,tiff,tif,jpg,jpeg,bmp,doc,docx') of
      0:   Result := 'image/png';
      1:   Result := 'image/gif';
      2,3: Result := 'image/tiff';
      4,5: Result := 'image/jpeg';
      6:   Result := 'image/bmp';
      7,8: Result := 'application/msword';
      else begin
        Result := RawUTF8(ExtractFileExt(FileName));
        if Result'' then begin
          Result[1] := '/';
          Result := 'application'+LowerCase(Result);
        end;
      end;
    end;
  end;
  if Result='' then
    Result := 'application/octet-stream';
end;

You can use a similar function, from the GAry Kessler's list.

Hello, buddy!

责编内容by:Hello, buddy! (源链)。感谢您的支持!

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