我如何知道什么数据库格式一个文件（或一组文件）（在Delphi中创建）？ [英] How can I tell what Database format a file (or set of files) was created with (in Delphi)?

问题描述

我有许多不同的程序创建的数据文件。是否有一种方法来确定用于创建数据文件的数据库的数据库和版本。

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.

例如，我想确定创建哪些文件从Microsoft Access，dBASE，FileMaker，FoxPro，SQLite或其他。

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

我真的只是想以某种方式快速扫描文件，并显示关于他们的信息，

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

作为参考，我使用Delphi 2009。

For reference, I'm using Delphi 2009.

推荐答案

p>首先，检查文件扩展名。请查看相应的维基百科文章或其他网站。

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

然后你可以从它所谓的签名猜出文件格式。

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

这大多是第一个字符的内容，档案格式。

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

您已在此非常好的Gary Kessler的网站。

例如，这里是我们的框架如何从文件内容中识别MIME格式，在服务器端：

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 (Content<>nil) 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;

您可以使用类似的函数，从GAry Kessler的列表。

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

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