向各位老师请教delphi保存图片问题？

Question

我用ORACLE 数据库，语言用DELPHI6.0
我用三层结构，请问我要把图片保存到数据库中，客户端我用clentdataset,请问各位老师怎么实现啊。
谢谢，我在线等后。

Answer 1

图片的字段用BLOB
图片存储问题.unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,jpeg,
  ExtDlgs, Db, DBTables, StdCtrls, ExtCtrls, ADODB;type
  TForm1 = class(TForm)
    Button1: TButton;
    OpenPictureDialog1: TOpenPictureDialog;
    Button2: TButton;
    Image1: TImage;
    ADOQuery1: TADOQuery;
    ADOQuery2: TADOQuery;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    filename:string;
    procedure SetPicture(pos:string;TempQuery:TADOQuery);     /////往数据库中插入图片
    procedure GetPicture(pos:string;TempQuery:TADOQuery);      ////得到图片
  end;var
  Form1: TForm1;implementation{$R *.DFM}{ TForm1 }procedure TForm1.GetPicture(pos:string;TempQuery: TADOQuery);
var
  MS_JpegStream:TMemoryStream;
begin
  try
    MS_JpegStream:=TMemoryStream.Create;
    with tempQuery do
      begin
        close;
        sql.clear;
        //修改这个语句
        sql.Add('select picture from table where no=:pos');
        Parameters.ParamByName('pos').value:=pos;
        Open;
      end;
    if tempquery.FieldByName('image').isnull then
      begin
        image1.Picture.Graphic:=nil;
      end
    else
      begin
         (tempQuery.FieldByName('image') as tblobfield).savetostream(MS_JpegStream);
         image1.Picture.Graphic:=nil;
         image1.Picture.Graphic:=TJpegImage.Create;
         MS_JpegStream.Position:=0;
         image1.Picture.Graphic.LoadFromStream(MS_JpegStream);
      end;  finally
    MS_JpegStream.Free;
  end;end;procedure TForm1.SetPicture(pos:string; TempQuery: TADOQuery);
var
  MS_JpegStream:TMemoryStream;
  M_BitMap:TBitMap;
  M_Jpeg:TJpegImage;
begin
  try
    MS_JpegStream:=TMemoryStream.Create;
    M_BitMap:=TBitMap.Create;
    M_Jpeg:=TJpegImage.Create;
    if extractfileext(filename)='.bmp' then
      begin
        M_BitMap.LoadFromFile(filename);
        M_Jpeg.Compress;
        M_Jpeg.Assign(M_BitMap);
      end
    else if extractfileext(filename)='.jpg' then
      begin
        M_Jpeg.LoadFromFile(filename);
      end;
    M_Jpeg.SaveToStream(MS_JpegStream);
    with tempQuery do
      begin
        close;
        sql.clear;
//修改这个语句
        sql.Add('insert into table (no,IMage) values (:pos,:image)');
        Parameters.ParamByName('pos').Value:=pos;
        Parameters.ParamByName('image').LoadFromStream(MS_JpegStream,ftblob);        ExecSQL;
      end;
  finally
    MS_JpegStream.Free;
    M_BitMap.Free;
    M_Jpeg.Free;
  end;
end;procedure TForm1.Button1Click(Sender: TObject);//打开图片并写入数据库
begin
  if openpicturedialog1.Execute then
  begin
   filename:=openpicturedialog1.FileName;
   SetPicture(edit1.text,ADOQuery1);
  end
end;procedure TForm1.Button2Click(Sender: TObject);//显示图片
begin
  getpicture(edit1.text,ADOQuery2);
end;end.

Answer 2

image字段
var
  strm : Tmemorystream;
begin
  if fileexists(openpicturedialog1.FileName) then
  begin
  strm := Tmemorystream.Create;
  strm.LoadFromFile(openpicturedialog1.FileName);
  strm.Position := 0;
  with dm.ClassMateQuery do
  begin
    append;
    TBlobfield(fieldbyname('pic')).LoadFromStream(strm);   
    post; 
  end;
  strm.Free;
  end;

Answer 3

TO：houwei1008(下雨天) 
有问题，编译时出错：Undeclared identifier:ftblob
                    Undeclared identifier:Tblobfield
                    Undeclared identifier:savetostream

Answer 4

添加：procedure Tstudent_Form.Button1Click(Sender: TObject);
var strm:Tmemorystream;
    jimg:Tjpegimage;
begin
  with d_module.student_Query do
    begin
      close;
      sql.Clear;
      sql.Add('select uid from user_info where study_no='''+edit1.Text+'''');
      open;  //检查数据表中是否存在同样的记录
      if eof and bof then
        begin
           close;
           strm:=Tmemorystream.Create;
          // image1.Picture.Graphic.SaveToStream(strm);
           jimg:=Tjpegimage.Create;
           if filename='' then filename:='default.jpg';
           jimg.LoadFromFile(filename);
           jimg.SaveToStream(strm);
           strm.Position:=0;
           sql.Clear;
           sql.Add('insert into user_info (study_no,uname,class_no,sex,fathername,');
           sql.Add('fathermobile,mothername,mothermobile,photo) values ('''+edit1.Text+'''');
           sql.Add(','''+edit2.Text+''','''+combobox1.Text+''','''+combobox2.Text+''','''+edit3.Text+''',');
           sql.Add(''''+edit4.Text+''','''+edit5.Text+''','''+edit6.Text+''',:a)');
           parambyname('a').LoadFromStream(strm,ftblob);
           //showmessage(sql.Text);
           execsql;
           jimg.Free;
           strm.Free;
           label10.Caption:='添加成功！';
           edit1.Text:='';
           edit2.Text:='';
           edit3.Text:='';
           edit4.Text:='';
           edit5.Text:='';
           edit6.Text:='';
           combobox1.ItemIndex:=-1;
           combobox2.ItemIndex:=-1;
        end
        else
         begin
             showmessage('对不起，该学号的学员信息已存在！');
             exit;
         end;
    end;
    d_module.search_student_Query.close;
    d_module.search_student_Query.open;
end;读取：procedure Tstudent_Form.N1Click(Sender: TObject);
var jpgimg:tblobstream;
    jpg:Tjpegimage;
begin
    button3.Enabled:=true;
   edit7.Text:=dbgrid1.SelectedField.AsString;
  // showmessage(edit7.Text);
   with d_module.student_Query do
     begin
         close;
         sql.Clear;
         sql.Add('select * from user_info where uid='+edit7.Text);
       //  showmessage(sql.Text);
         open;
         edit1.Text:=fieldbyname('study_no').AsString;
         edit2.Text:=fieldbyname('uname').AsString;
         //combobox1.Text:=fieldbyname('class_no').AsString;
         combobox1.ItemIndex:=combobox1.Items.IndexOf(fieldbyname('class_no').AsString);
         combobox2.ItemIndex:=combobox2.Items.IndexOf(fieldbyname('sex').AsString);
         edit3.Text:=fieldbyname('fathername').AsString;
         edit4.Text:=fieldbyname('fathermobile').AsString;
         edit5.Text:=fieldbyname('mothername').asstring;
         edit6.Text:=fieldbyname('mothermobile').asstring;
         if fieldbyname('photo').IsNull then
            image1.Picture.LoadFromFile('AC_ba.jpg')
         else
           begin
              jpgimg:=tblobstream.Create(tblobfield(fieldbyname('photo')),bmread);
             // Tblobfield(fieldbyname('photo')).savetostream(jpgimg);
              jpgimg.Position:=0;
              image1.Picture.Graphic:=nil;
              jpg:=Tjpegimage.Create;
              jpg.LoadFromStream(jpgimg);
              image1.Picture.Graphic:=jpg;
              jpg.Free;
              jpgimg.Free;
           end;
         close;
     end;   // combobox1.Items.
end;注意在uses中引用：
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids,Db, DBTables, DBGrids, Menus,Jpeg, ExtCtrls, ExtDlgs,ADODB;没错的，我现在就这么写的，但是当图片太大时，有点问题，有部分图片显示不出来，应该是没有存进去。

Answer 5

说明：filename是定义的一个全局变量，通过openpicturedialog取值的。