数据库中的jpg的问题？写、读？

[jiangjian0427]

请问怎么向数据库里面添加jpg图片啊？好像delphi对图形的支持不太好

[helodd]

dbimage1.LoadPicture

[huojiehai]

增加：


Query.Close;
Query.SQL.Clear;
Query.SQL.Add('INSERT INTO myimages(FileName,pic) VALUE(''Image1'',:pic)');
Query.ParamByName('pic').LoadFromFile('D:\Hasd.bmp',ftBlob);
Query.ExecSQL;

　

修改：

Query.Close;
Query.SQL.Clear;
Query.SQL.Add('UPDATE myimages SET pic=:pic WHERE filename=''Image1''');
Query.ParamByName('pic').LoadFromFile('D:\Hasd2.bmp',ftBlob);
Query.ExecSQL;

[Maple119]

这个我不太会.但我会一种笨笨的办法.

将一图形文件当作二进数据读出来,然后写到备注型文件中去.

[dickeybird888]

哈哈
（·￥·）
huojiehai(海天子)
你好啊！

[jiangjian0427]

to huojiehai(海天子)
请问：你说的对jpg支持吗？你写的是bmp啊
还有是LoadFromFile();只有一个参数

[立志做一个佳娃~]

为了支持JPEG文件格式首先得在uees中加入jpeg单元。

uses jpeg;

[huojiehai]

这是保存文件，什么文件都可以

[aiirii]

to jiangjian0427(carabao) :
huojiehai(海天子) 用的是保存文件名的方法, 那就無所謂是什麼文件了!!

也許這種實現不是很好吧, 看需求, 正常, 也可直接用流寫到數據庫, 然後, 同樣用流讀出,再寫入到 Image 類

[aiirii]

補充一句,
>>好像delphi对图形的支持不太好
好象是吧, 但至少對JPG支持還很好的, 在Access, MsSql2000上, 我實現我如上的方法都很正常!!

[RockEx]

　　
　　　　　　　　　　　　　　　　　　　　　　DELPHI存取JPEG文件到SQL Server数据库
　　　　　　　　　　　　　　　　　　　　　　　　　　
　

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;
　　到此用DELPHI存取JPEG文件到SQL Server数据库中的具体操作已经叙述完毕。



　　　　　　　　　　　　　　　　　　
　　　　　　　　　　　　　　　　　　　　　DELPHI存取JPEG文件到SQL Server数据库(续文)
　　　　　　　　　　　　　　　　　　　　　　　　
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Db, DBCtrls, Grids, DBGrids, ADODB, ExtDlgs,jpeg, ExtCtrls, StdCtrls;

type
TForm1 = class(TForm)
ADOConnection1: TADOConnection;
ADOQuery1: TADOQuery;
DataSource1: TDataSource;
DBGrid1: TDBGrid;
DBImage1: TDBImage;
ADOQuery1ID: TStringField;
ADOQuery1FIELD: TStringField;
ADOQuery1STYLE: TStringField;
ADOQuery1SYSTEM: TStringField;
ADOQuery1DATE: TDateTimeField;
ADOQuery1PERSON1: TStringField;
ADOQuery1PERSON2: TStringField;
ADOQuery1PERSON3: TStringField;
ADOQuery1PHOTO: TBlobField;
ADOQuery1DESCRIPTION: TStringField;
OpenPictureDialog1: TOpenPictureDialog;
Image1: TImage;
Button1: TButton;
Memo1: TMemo;
procedure DBImage1Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure FormShow(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.DBImage1Click(Sender: TObject);
var
picstream:tadoblobstream;
bmppic:tbitmap;
jpgpic:tjpegimage;
bmpstream:TMemoryStream;
begin
if form1.OpenPictureDialog1.Execute then
begin
if extractfileext(form1.openpicturedialog1.filename)='.bmp' then
begin
adoquery1.edit;
picstream:=tadoblobstream.Create(tblobfield(ADOQuery1PHOTO),bmWrite);
//注：上句代码中的ADOQuery1PHOTO是adoquery1中的固定字段photo的固定字段的name
//用户需要手工添加固定字段，也可用fields[i]来进行选择，这点在
//"DELPHI存取JPEG文件到SQL Server数据库"这篇文章中没有注释，至使许多朋友没有
//编译成功。
picstream.LoadFromFile(openpicturedialog1.filename);
picstream.Position:=0;
adoquery1.edit;
tblobfield(ADOQuery1PHOTO).loadfromstream(picstream);
adoquery1.post;
adoquery1.edit;
picstream.free;
end
else
begin
jpgpic:=tjpegimage.Create;
bmppic:=tbitmap.Create;
bmpstream:=tmemorystream.Create;
jpgpic.LoadFromFile(openpicturedialog1.filename);
bmppic.Assign(jpgpic);
bmppic.SaveToStream(bmpstream);
adoquery1.edit;
picstream:=tadoblobstream.Create(tblobfield(ADOQuery1PHOTO),bmWrite);
//注：上句代码中的ADOQuery1PHOTO是adoquery1中的固定字段photo的固定字段的name
//用户需要手工添加固定字段，也可用fields[i]来进行选择，这点在
//"DELPHI存取JPEG文件到SQL Server数据库"这篇文章中没有注释，至使许多朋友没有
//编译成功。
picstream.LoadFromStream(bmpstream);
picstream.Position:=0;
adoquery1.edit;
tblobfield(ADOQuery1PHOTO).loadfromstream(picstream);
adoquery1.post;
jpgpic.free;
bmppic.free;
bmpstream.free;
adoquery1.edit;
picstream.free;
end;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
memo1.Lines.Add(form1.openpicturedialog1.filter);
end;

procedure TForm1.FormShow(Sender: TObject);
begin
form1.openpicturedialog1.filter:='All *.jpg;*.jpeg;*.bmp;|*.jpg;*.jpeg;*.bmp;)';
end;

end.