Delphi 10, Digital Persona and MySQL

Question

我现在处于智慧的尽头。我到处寻找一种使用Digital Persona SDK（One Touch）和Delphi 10验证MySQL数据库中捕获的指纹的方法。我可以将指纹保存为数据库中的长blob，但无法从数据库中进行验证。希望这里有人能够帮助我。读者是U.Are.U 4500。

下面是我用来保存指纹的代码，但是当我需要再次验证指纹时，我不知道如何查询数据库。

procedure TForm1.FPCaptureComplete(ASender: TObject;
const ReaderSerNum: WideString; const pSample: IDispatch);
var
    l_interface : IDispatch;
    outFile : File;
    vt : integer ;
    vtByteBuf : PByteArray;   
    aryLow : integer;
    aryHigh : integer;
    rawDataSize: integer;
    loopIndex : integer;
begin
l_interface := FPGetImage.ConvertToPicture(pSample);
lblInfo.Caption:='Sample Captured';
SetOlePicture(pbPrint.Picture,IPictureDisp(l_interface));  //display print
if breginprogress=true then begin
if index > 4 then index:=1;     //reset index if beyond 4 presses
if index=1 then
begin
lbl1.Font.Color:=clGreen;
lbl2.Font.Color:=clYellow;
 end;
 if index=2 then
begin
lbl2.Font.Color:=clGreen;
lbl3.Font.Color:=clYellow;
 end;
  if index=3 then
begin
lbl3.Font.Color:=clGreen;
lbl4.Font.Color:=clYellow;
end;
if index=4 then lbl4.Font.Color:=clGreen;
index := index + 1;
//Create registrationenrollment featureset from sample captured
       try
 FPExtraction.CreateFeatureSet(pSample,DataPurposeEnrollment);
       except
            on E: Exception do  begin
            showmessage('Exception inside CreateFeatureSet');
            showmessage(E.Message);
            FPregister.Clear;
            ResetLabels;
            index:=1;
            exit;
             end;
       end;
if FPExtraction.FeatureSet <> nil then
 //Add features to registration object
 FPRegister.AddFeatures(FPExtraction.FeatureSet)
 else begin
 Showmessage('Could not create featureset, poor press');
 FPRegister.Clear;
 ResetLabels;
 index:=1;
 exit;  //return
 end;
 //If 4 successful features added, status should be 'Ready'
 if FPRegister.TemplateStatus=TemplateStatusTemplateReady then  begin
    lblResult.Caption:='User Enrolled - Press Finger for Verification';
    lbl1.Visible:=false; lbl2.Visible:=false; lbl3.Visible:=false;       lbl4.Visible:=false;
    FPTemplate:=FPRegister.Template as DPFPShrXLib_TLB.DPFPTemplate;
    breginprogress:=false;  //stop registration process, enable verification
    //Before saving data to database you will need to get the raw data    (variant)
    try
    vrnt:=FPTemplate.Serialize;  //raw data is now stored in this variant

    aryLow:=VarArrayLowBound(vrnt,1);
    aryHigh:=varArrayHighBound(vrnt,1);
    aryHigh:=aryHigh-aryLow;
    vtByteBuf:=VarArrayLock(vrnt);  //lock down the array
    for loopIndex := 0 to aryHigh - 1 do
           fpData[loopIndex]:=vtByteBuf[loopIndex];
    VarArrayUnlock(vrnt);
    //Save fpData to database here
    //Database logic is not provided here.  Plenty examples on web on
    //How to save a byte array (binary data) to database.
    SaveFP;
    except
    on E: Exception do showmessage('Trouble saving data');
    end;
end;
end;
end;
//This is the pysical save
procedure TForm1.SaveFP;
var
tptStream: TMemoryStream;
p: Pointer;
begin
MemberTbl.Insert;
MemberTbl.FieldByName('MemberName').AsString := NameEdit.Text;
tptStream := TMemoryStream.Create();
tptStream.Position := 0;
p := VarArrayLock(vrnt);
tptStream.Write(p^, VarArrayHighBound(vrnt, 1));
VarArrayUnlock(vrnt);
(MemberTbl.FieldByName('MemberFP') as  BlobField).LoadFromStream(tptStream);
MemberTbl.Post;
tptStream.Free();
end;

Answer 1

我已经为Windows SDK版本1.6.1的DigitalPersona One Touch创建了一个组件包装器（2010年8月）

我已经用DigitalPersona U.are.U 4000B阅读器

进行了测试，但根据文档，它也应该与DigitalPersona U.are.U 4500阅读器一起使用。

您可以在此处查看并下载组件

然后，您可以在 OnCaptured 事件处理程序上添加如下代码：

procedure TForm1.DPFingerPrintReader1Captured(Reader: TDPFingerPrintReader; FingerComparer: IFingerComparer);
var
  LFingerPrintField: TField;
begin
    LFingerPrintField := YourDataSet.FieldByName('FingerPrintField');
    while not YourDataSet.Eof do
    begin
      if FingerComparer.CompareTo(LFingerPrintField.AsString) then
      begin
        ShowMessage('Found');
        Exit;
      end;
      YourDataSet.Next;
    end;    
    ShowMessage('NOT Found');
end;