如何存取图片到sql server图片格式最好是jpg的。

Question

DBIMage好象不能直接支持JPG格式?!

Answer 1

用流来解决，然后判断流的起始标识符号，然后建立相应的显示图片的类，最后将图片转入到DBImage即可！

Answer 2

unit Ffactwin;interfaceuses
  SysUtils, Windows, Messages, Classes, Graphics, Controls,
  Forms, StdCtrls, DBCtrls, DBGrids, DB, DBTables, Buttons, Grids, ExtCtrls,
  Menus, ExtDlgs, Dialogs;type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Label1: TLabel;
    DBLabel1: TDBText;
    DBMemo1: TDBMemo;
    DataSource1: TDataSource;
    Table1: TTable;
    Table1Common_Name: TStringField;
    Table1Graphic: TBlobField;
    DBGrid1: TDBGrid;
    BitBtn1: TBitBtn;
    Table1Category: TStringField;
    Table1SpeciesName: TStringField;
    Table1Lengthcm: TFloatField;
    Table1Length_In: TFloatField;
    Table1Notes: TMemoField;
    ImageFish: TImage;
    PopupMenuImage: TPopupMenu;
    MenuImageLoad: TMenuItem;
    N2: TMenuItem;
    MenuImageConvertBitmap: TMenuItem;
    MenuImageConvertGIF: TMenuItem;
    MenuImageConvertJPEG: TMenuItem;
    OpenPictureDialog: TOpenPictureDialog;
    procedure DataSource1DataChange(Sender: TObject; Field: TField);
    procedure MenuImageConvertBitmapClick(Sender: TObject);
    procedure MenuImageConvertGIFClick(Sender: TObject);
    procedure MenuImageConvertJPEGClick(Sender: TObject);
    procedure MenuImageLoadClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    procedure UpdateField(Graphic: TGraphic);
  public
  end;var
  Form1: TForm1;implementation{$R *.DFM}uses
  GIFImage,
  JPEG,
  ClipBrd;{ Paradox graphic BLOB header - from db.pas }type
  TGraphicHeader = record
    Count: Word;                { Fixed at 1 }
    HType: Word;                { Fixed at $0100 }
    Size: Longint;              { Size not including header }
  end;  TGraphicHack = class(TGraphic);
  TGraphicHackClass = class of TGraphicHack;  TImageSignature = record
    ImageType: TGraphicClass;
    Name: string;
    Signature: string;
  end;const
  Signatures: array[0..2] of TImageSignature
    = ((ImageType: TBitmap; Name: 'Bitmap'; Signature: 'BM'),
       (ImageType: TGIFImage; Name: 'GIF'; Signature: 'GIF'),
       (ImageType: TJPEGImage; Name: 'JPEG';
        Signature: chr($FF)+chr($D8)+chr($FF)+chr($E0)+chr($00)+chr($10)+'JFIF'));procedure TForm1.FormCreate(Sender: TObject);
begin
  Table1.Open;
end;procedure TForm1.DataSource1DataChange(Sender: TObject; Field: TField);
var
  Stream : TStream;
  Size : integer;
  Header : TGraphicHeader;
  Signature : pointer;
  i : integer;
  Image : TGraphic;
  Name : string;
begin
  if ((Field <> nil) and (Field <> Table1Graphic)) or
    (Table1Graphic.DataSet.State <> dsBrowse) then
    exit;  Image := nil;  // Database cursor has moved - Update image
  Stream := Table1Graphic.DataSet.CreateBlobStream(Table1Graphic, bmRead);
  try
    // Skip paradox image header
    Size := Stream.Size;
    if (Size >= SizeOf(TGraphicHeader)) then
    begin
      Stream.Read(Header, SizeOf(Header));
      if (Header.Count <> 1) or (Header.HType <> $0100) or
        (Header.Size <> Size - SizeOf(Header)) then
        Stream.Seek(-SizeOf(Header), soFromCurrent);
    end;    try
      // Determine image type from file signature
      for i := low(Signatures) to high(Signatures) do
      begin
        if (length(Signatures[i].Signature) > Size) then
          continue;
        // Read signature
        GetMem(Signature, length(Signatures[i].Signature));
        try
          Stream.Read(Signature^, length(Signatures[i].Signature));
          // Reposition stream cursor
          Stream.Seek(-length(Signatures[i].Signature), soFromCurrent);
          // Compare signatures
          if (CompareMem(Signature, @Signatures[i].Signature[1], length(Signatures[i].Signature))) then
          begin
            Image := TGraphicHackClass(Signatures[i].ImageType).Create;
            Name := Signatures[i].Name;
            break;
          end;
        finally
          Freemem(Signature);
        end;
      end;      // Force TImage to desired graphic type
      ImageFish.Picture.Graphic := Image;      // Load image from stream
      if (ImageFish.Picture.Graphic <> nil) then
      begin
        ImageFish.Picture.Graphic.LoadFromStream(Stream);
        Caption := format('FISH FACTS - %s image, %d bytes', [Name, Size]);
      end else
        Caption := 'FISH FACTS';    finally
      Image.Free;
    end;
  finally
    Stream.Free;
  end;
end;// Write the specified image to the BLOB field
procedure TForm1.UpdateField(Graphic: TGraphic);
var
  Stream : TStream;
  Header : TGraphicHeader;
begin
  Table1Graphic.DataSet.Edit;
  Stream := Table1Graphic.DataSet.CreateBlobStream(Table1Graphic, bmWrite);
  try
    // TBitmaps are saved in a special format which is compatible with
    // the TDBImage component...
    if (Graphic is TBitmap) and
      ((Table1Graphic.DataType = ftGraphic) or (Table1Graphic.DataType = ftTypedBinary)) then
    begin
      Stream.Write(Header, SizeOf(Header));
      Graphic.SaveToStream(Stream);
      Header.Count := 1;
      Header.HType := $0100;
      Header.Size := Stream.Position - SizeOf(Header);
      Stream.Position := 0;
      Stream.Write(Header, SizeOf(Header));
    end else
      // ...all other image formats are just saved to the BLOB stream
      Graphic.SaveToStream(Stream);
  finally
    Stream.Free;
  end;
  Table1Graphic.DataSet.Refresh;
end;procedure TForm1.MenuImageConvertBitmapClick(Sender: TObject);
var
  Bitmap : TBitmap;
begin
  Bitmap := TBitmap.Create;
  try
    Bitmap.Assign(ImageFish.Picture.Graphic);
    UpdateField(Bitmap);
  finally
    Bitmap.Free;
  end;
end;procedure TForm1.MenuImageConvertGIFClick(Sender: TObject);
var
  GIF : TGIFImage;
begin
  GIF := TGIFImage.Create;
  try
    GIF.ColorReduction := rmQuantize;
    GIF.DitherMode := dmFloydSteinberg;
    GIF.Assign(ImageFish.Picture.Graphic);
    UpdateField(GIF);
  finally
    GIF.Free;
  end;
end;procedure TForm1.MenuImageConvertJPEGClick(Sender: TObject);
var
  JPEG : TJPEGImage;
  Bitmap : TBitmap;
begin
  JPEG := TJPEGImage.Create;
  try
    // TJPEGImage can only assign from TBitmap and TJPEGImage, so we
    // need to convert the TGIFImage to a TBitmap before it can be
    // converted to a TJPEGImage
    if (ImageFish.Picture.Graphic is TGIFImage) then
    begin
      Bitmap := TBitmap.Create;
      try
        Bitmap.Assign(ImageFish.Picture.Graphic);
        JPEG.Assign(Bitmap);
      finally
        Bitmap.Free;
      end;
    end else
      JPEG.Assign(ImageFish.Picture.Graphic);
    JPEG.CompressionQuality := 80;
    JPEG.Compress;
    UpdateField(JPEG);
  finally
    JPEG.Free;
  end;
end;procedure TForm1.MenuImageLoadClick(Sender: TObject);
begin
  if (OpenPictureDialog.Execute) then
  begin
    ImageFish.Picture.LoadFromFile(OpenPictureDialog.FileName);
    UpdateField(ImageFish.Picture.Graphic);
  end;
end;end.

Answer 3

用二进制方式打开文件，直接写入数据库，字段类型也是Image的。

Answer 4

谢谢星星农场，不过你用的是TABLE控件，我特别说了，我不用TABLE控件，我用的是QUERY，我想知道为什么把TSTREAM类通过QUERY.PARAMABYNAME.LOADSTREAM装入后执行SQL就报错。

Answer 5

可以式式
Query1.Params[n].ASBlob:=Buffer;
或
Query1.Params[n].LoadfromStream;
再不行就
Query1.Params[n].setBolbData;
应该都可以
注意要把
Query1.Params[n].DataType设成你的类型，比如ftBlob或ftGraphic

Answer 6

我已经解决问题，程序如下：
use jpeg
var
   tp_stream: tmemorystream;
begin
   tp_stream.create;
   query1.close;
   .........
   image.picture.savetostream(tp_stream);
   query1.parambyname(':变量名').loadstream:=tp_stream;
   query1.sql.execsql;
   query1.close;
end;

Answer 7

上面的程序有敲错的地方，大家在DELPHI里会自动给出的。