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How to save the image into the database in Delphi7?

Posted on 2003-12-10
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Last Modified: 2007-12-19
Hi ,
  the function I want is to save the picture in Timage object to the sql database, I have tried several ways to do it ,but not successful.

the picture I load from file may be jpg ,bmp or emf,wmf.  
I look up some references , most of them told me to do like this below:
MS:TmemoryStream;
pic:TGraphic.

image1.picture.bitmap.loadfromfile(filename);
//or pic:=Tgraphic.create;
//    pic.loadfromfile(filename)
image1.picture.bitmap.savetostream(ms);
ms.position:=0;
table1.open;
table1.insert; // or append;
TBolbfield(table1.fieldbyname('image')).loadfromstream(ms);
// or table1.fieldbyname('image').assign(pic);
table1.post;
table1.close;
ms.free;
pic.free;

it works if the picture I load fromis the bitmap file,otherwise If the image is loaded from a jpg file, the exception "bitmap is not valid" comes out;

I have also tried to use TGraphic to load the file, it even failed when I  try to load a jpg file in it.

I am so confused now ,pls tell me what to do .My enviroment"
win2k pro, delphi7. sqlserver 2000;


Regards,
Sam
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Question by:Sam80
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7 Comments
 
LVL 5

Expert Comment

by:snehanshu
ID: 9918522
Sam80,
  TImage does not support JPEG files.
  Use TJpegImage for image1.
  i.e.

Var
  MyImg : TJpegImage;
Begin
...
  MyImg := TJpegImage.Cleate;
  MyImg.LoadFromFile('MyImg.jpg');
  MyImg.SaveToStream(MS);
 
...


*-*-*-*-*

Also, remember to add jpeg in uses .


HTH,
...Shu
0
 
LVL 5

Expert Comment

by:delphized
ID: 9918685
I think it's better:

var
  F:TFileStream;
begin
  F:=TFileStream.create('YourFileNameHere',fmOpenRead);
  //...
  TBolbfield(table1.fieldbyname('image')).loadfromstream(F);
  //...
  F.free;
0
 

Author Comment

by:Sam80
ID: 9919217
Thank you for your suggestion.

I wanna load both jpeg and bitmap file , further more , load the file in the openpicturedialg supported format(emf,wmf), not just a single format and neednt  specify different way to load the different format file . I will try the TFileStream later.    

Thank you all .

Regards,
Sam
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LVL 17

Expert Comment

by:geobul
ID: 9919818
Hi,

Just add jpeg to your uses clause and keep using TImage. This works fine here.

Regards, Geo
0
 

Author Comment

by:Sam80
ID: 9925882
I have use Tbitmap to load the picture in the TImage. And then use table.fieldbyna,e('image').assign(bmp) to save the img to the database.

but I now doubt there will be a mess data in the database for all the image format is bitmap.

================

To Geo,
  In delphi7 , I dont have to add the jpeg unit and use Tjpegimage as well.  but if i add that unit, delphi report that there has no such unit.

To delphized,
  I have try your method , but it's so strange that I read the jpeg file into a memorystream type object and save it into the field like the way you show to me , but in that step , the exception message "bitmap is not valid " still comes out,in contrast , if i save a bitmap memorystream, it works !! . I doubt it's the database's problem . in my sql, I define the field "image" as image type, length is 16. why it can verify my memorystream is bitmap or not??

To all ,
    The another problem I meet  is the Tgraphic problem. I cannot use Tgraphic.loadfromfile because of the error "abstract error" . I have tried to do :   gra:Tgraphic;
gra:=Tgraphic.create;
gra:=Timage.picture.Graphic; // not gra.assign(..)
in this way, the gra has the picture's width and height same as that in Timage  !

Regards,
Sam
0
 
LVL 5

Expert Comment

by:delphized
ID: 9926479
I told you TFileStream... and I didn't know you were usin a Image field (Ithought a blob field).

You can't use the TGraphic method because TGraphic is a abstract class that is derived in different subclasses for every king of image (bitmab,jpeg, ...).

After having known this last information, you could make this way;

var
  bmp:TBitmap;
begin
  bmp:=TBitmap.create;
  bmp.height:=Image1.picture.height;
  bmp.width:=Image1.picture.width;
  bmp.canvas.draw(0,0,Image1.picture);
 
and then assign the bmp object to your field

  bmp.free;
end;
0
 
LVL 1

Accepted Solution

by:
hederglan earned 80 total points
ID: 9933951
Hi, Sam80!

I had the same problem some weeks ago...but I found a solution that works fine.
Above follows the code to save and to load an image using BlobFields and TImage...
This code has some functions that were designed specificly for JPEG format......when we are working with JPEG format and MicroSoft Databases we have problems: MS DBs add headers to the blob field making the image unreadable (they are readable only by MS DBs)....to read these images we have to eliminate the readers in the reading process...
But if you work with a bmp or any other all you have to do is not use the jpeg's functions....

So, here is the code:

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    ADOTable1: TADOTable;
    DataSource1: TDataSource;
    btnShowImage: TButton;
    ADOImage: TImage;
    ADOTable1Name: TWideStringField;
    ADOTable1Description: TWideStringField;
    ADOTable1Author: TWideStringField;
    ADOTable1Type: TWideStringField;
    ADOTable1Size: TFloatField;
    ADOTable1Cost: TBCDField;
    ADOTable1DateUpl: TDateTimeField;
    ADOTable1Picture: TBlobField;
    DBGrid1: TDBGrid;
    procedure btnShowImageClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
     { Public declarations }
  end;


const
 JPEGstarts = 'FFD8';
 BMPstarts = '424D';  //BM

var
  Form1: TForm1;

implementation
uses jpeg;
 {$R *.DFM}

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

procedure TForm1.btnShowImageClick(Sender: TObject);
var
  bS  : TADOBlobStream;
  Pic : TJpegImage;
begin
  bS := TADOBlobStream.Create(AdoTable1Picture, bmRead);
  try
    bS.Seek(JpegStartsInBlob(AdoTable1Picture), soFromBeginning);
    Pic:=TJpegImage.Create;
    try
     Pic.LoadFromStream(bS);
     ADOImage.Picture.Graphic:=Pic;
    finally
     Pic.Free;
    end;
  finally
    bS.Free
  end;
end;


procedure TForm1.FormCreate(Sender: TObject);
var sDBPath, sCons: string;
begin
//change the sDBPath to point to your database!
sDBPath := 'c:\!Gajba\About\aboutdelphi.mdb';
sCons := 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=' + sDBPath + ';Persist Security Info=False';

ADOTable1.ConnectionString := sCons;
ADOTable1.TableName := 'Applications';
DataSource1.DataSet := ADOTable1;
DBGrid1.DataSource := DataSource1;

ADOTable1.Active:=True;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  ADOTable1.Active:=False;
end;


//Extra!! save JPG to table
procedure SaveJpegToTable(Table: TADOTable; PicField:TBlobField; sPicPath: string);
{
Usage:

  SPicFileName := 'C:\!gajba\cdcovers\cdcover1.jpg';
  SaveJpegToTable(ADOTable1, ADOTable1Picture, SPicFileName);
}
var
  fS  : TFileStream;
begin
  fs:=TFileStream.Create(sPicPath, fmOpenRead);
  try
   Table.Edit;
   PicField.LoadFromStream(fs);
   Table.Post;
  finally
   fs.Free;
  end;
end;


end.
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