如何从数据库存取图片文件

[songdan2002]

如何将JPG格式的图片数据流放入数据库，如何从数据库取出将JPG格式的图片数据流

[glfwyz]

为了争取第一,拷了人家的:)
用ADO控件存取SQL Server数据库图片，查看资料发现基本都是针对BMP文件进行操作(巨增数据库大小)，但源码如下：
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, DBCtrls, Grids, DBGrids, Db, ADODB,jpeg, StdCtrls,dbtables;
{一定要USES JPEG单元,使能存储JPG文件格式}
type
TForm1 = class(TForm)
DataSource1: TDataSource;
ADOQuery1: TADOQuery;
DBGrid1: TDBGrid;
DBNavigator1: TDBNavigator;
Image1: TImage;
savebutton: TButton;
showbutton: TButton;
OpenDialog1: TOpenDialog;
ADOQuery1id: TIntegerField;
ADOQuery1pic: TBlobField;
procedure savebuttonClick(Sender: TObject);
procedure showbuttonClick(Sender: TObject);
procedure DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

function JpegStartsInBlob(PicField:TBlobField):integer;
var
ghy: TADOBlobstream;
buffer:Word;
hx: string;
begin
Result := -1;
ghy := TADOBlobstream.Create(PicField, bmRead);
try
while (Result = -1) and (ghy.Position + 1 < ghy.Size) do
begin
ghy.ReadBuffer(buffer, 1);
hx:=IntToHex(buffer, 2);
if hx = ’FF’ then begin
ghy.ReadBuffer(buffer, 1);
hx:=IntToHex(buffer, 2);
if hx = ’D8’ then Result := ghy.Position - 2
else if hx = ’FF’ then
ghy.Position := ghy.Position-1;
end; //if
end; //while
finally
ghy.Free
end; //try
end;


procedure TForm1.savebuttonClick(Sender: TObject);
var
picstream:tadoblobstream;
begin
adoquery1.edit;
picstream:=tadoblobstream.Create(tblobfield(adoquery1.fields[1]),bmWrite);
if form1.opendialog1.execute then
begin
picstream.LoadFromFile(opendialog1.filename);
picstream.Position:=0;
adoquery1.edit;
tblobfield(adoquery1.Fields[1]).loadfromstream(picstream);
adoquery1.post;
end;


end;

procedure TForm1.showbuttonClick(Sender: TObject);
var
ghy:TADOBlobstream;
pic:tjpegimage;
begin
ghy := TADOBlobstream.Create(Adoquery1pic, bmRead);
try
ghy.Seek(JpegStartsInBlob(Adoquery1pic),soFromBeginning);
Pic:=TJpegImage.Create;
try
Pic.LoadFromStream(ghy);
Image1.Picture.Graphic:=Pic;
finally
Pic.Free;
end;
finally
ghy.Free
end;
end;

procedure TForm1.DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
begin
if button in [nbFirst, nbPrior, nbNext, nbLast] then showbutton.Click;
end;

end.

如果数据库中要存储的是BMP文件，则在procedure TForm1.showbuttonClick(Sender: TObject);过程中代码更改如下即可存储显示BMP文件格式的操作。
procedure TForm1.showbuttonClick(Sender: TObject);
var
ghy:TADOBlobstream;
pic:tbitmap;
begin
ghy := TADOBlobstream.Create(Adoquery1pic, bmRead);
try
{ ghy.Seek(JpegStartsInBlob(Adoquery1pic),soFromBeginning);}
Pic:=Tbitmap.Create;
try
Pic.LoadFromStream(ghy);
Image1.Picture.Graphic:=Pic;
finally
Pic.Free;
end;
finally
ghy.Free
end;
end;

[zhangxinji]

给你段代码，看那两个事件的代码就行，如果想处理jpg，那就加jpeg单元

unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, DBCtrls, StdCtrls, Mask, DB, ExtCtrls, DBTables, ExtDlgs;
type TForm1 = class(TForm)
Table1: TTable;
Panel1: TPanel;
DataSource1: TDataSource;
Table1NAME: TStringField;
Table1SIZE: TSmallintField;
Table1WEIGHT: TSmallintField;
Table1AREA: TStringField;
Table1BMP: TBlobField;
Label1: TLabel;
DBEdit1: TDBEdit;
Label2: TLabel;
DBEdit2: TDBEdit;
Label3: TLabel;
DBEdit3: TDBEdit;
Label4: TLabel;
DBEdit4: TDBEdit;
Label5: TLabel;
DBImage1: TDBImage;
DBNavigator1: TDBNavigator;
Button1: TButton;
Button2: TButton;
OpenPictureDialog1: TOpenPictureDialog;
procedure Button2Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
private { Private declarations }
public { Public declarations }
end;
var Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button2Click(Sender: TObject);
begin if OpenPictureDialog1.Execute then
begin
table1.Edit;
//DBImage1.Picture.LoadFromFile(OpenPictureDialog1.FileName); TBlobField(table1.FieldByName('bmp')).LoadFromFile(OpenPictureDialog1.FileName); table1.Post;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin if OpenPictureDialog1.Execute then
begin
table1.Edit;
//DBImage1.Picture.LoadFromFile(OpenPictureDialog1.FileName);
//使用TBLOBFIELD类实现保存图象
TBlobField(table1.FieldByName('bmp')).LoadFromFile(OpenPictureDialog1.FileName); table1.Post;
end;
end;
end.

[karach]

glfwyz()你的代码可是我的哦，代码再http://expert.csdn.net/Expert/topic/2070/2070079.xml?temp=9.132022E-02
karach(卡车）