如何在MSSQL中使用image字段进行jpg图片存取？

//===========================================================================

// 数据库结构如下

//---------------------------------------------------------------------------

// if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[Tbl_RealTimeDataInterFace]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)

// drop table [dbo].[Tbl_RealTimeDataInterFace]

// GO

//

// CREATE TABLE [dbo].[Tbl_RealTimeDataInterFace] (

// [Id] [int] IDENTITY (1, 1) NOT NULL ,

// [WheelNum] [tinyint] NULL ,

// [PictureName] [varchar] (200) COLLATE Chinese_PRC_CI_AS NULL ,

// [Picture] [image] NULL ,

// ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

// GO

//---------------------------------------------------------------------------

//===========================================================================

// 参考网站

//---------------------------------------------------------------------------

// http://community.csdn.net/Expert/topic/4817/4817560.xml?temp=.8010218

//---------------------------------------------------------------------------

/*

*===========================================================================

* AuthorFeng Weizhao

* Date 2006/12/15

*

* 功能: BCB 6 环境下SQL数据库中jpg图片存入,显示

*

*===========================================================================

*/

TForm1 *Form1;

//---------------------------------------------------------------------------

__fastcall TForm1::TForm1(TComponent* Owner)

: TForm(Owner)

{

}

//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)

{

/* ok

AnsiString Sql = "select top 1 * from Tbl_RealTimeDataInterFace order by id desc ";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

// ADOQuery1->Append();

TBlobField *blob=(TBlobField *)ADOQuery1->FieldByName("Picture");

blob->LoadFromFile("StillCap001.jpg");

ADOQuery1->Post();

*/

try{

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = "insert into Tbl_RealTimeDataInterFace (WheelNum,Picture) values (2,:picture)";

ADOQuery1->Parameters->ParamByName("picture")->LoadFromFile("StillCap001.jpg",ftBlob);

ADOQuery1->ExecSQL();

}catch(...){

ShowMessage("写入数据库错误");

}

/* not ok

AnsiString Sql = "select top 1 * from Tbl_RealTimeDataInterFace order by id desc";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

ADOQuery1->Edit();

TBlobField *pField = (TBlobField *)ADOQuery1->Parameters->ParamByName("Picture");

TBlobStream *pmem = new TBlobStream(pField, bmWrite);

pmem->Seek(0,soFromBeginning);

pField->SaveToStream(pmem);

Graphics::TBitmap *pBitmap = new Graphics::TBitmap();

pBitmap->Assign(Image1->Picture->Graphic);

pBitmap->SaveToStream(pmem);

ADOQuery1->Post();

*/

}

//---------------------------------------------------------------------------

void __fastcall TForm1::Button2Click(TObject *Sender)

{

try{ // 不成功

AnsiString Sql = "select top 1 * from Tbl_RealTimeDataInterFace order by [id] desc ";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

TMemoryStream *Stream = new TMemoryStream();

Stream->Seek(0,soFromBeginning);

TBlobField *blob = (TBlobField *)ADOQuery1->FieldByName("Picture");

blob->SaveToStream(Stream);

Image2->Picture->Bitmap->LoadFromStream(Stream);

}catch(...){}

}

//---------------------- 通过文件读出 jpg 文件-----------------------------------------------------

void __fastcall TForm1::btn_1Click(TObject *Sender)

{

AnsiString Sql = "select top 1 * from Tbl_RealTimeDataInterFace order by [id] desc ";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

TBlobField *blob = (TBlobField *)ADOQuery1->FieldByName("Picture");

blob->SaveToFile("aa.jpg");//或者SaveToStream(xxx);

Image2->Picture->LoadFromFile("aa.jpg");//或者LoadFromStream(xxx);

}

//---------------------------- 直接从内存中读出jpg文件 ----------------------------------------------

void __fastcall TForm1::Button6Click(TObject *Sender)

{

AnsiString Sql = "select top 1 * from Tbl_RealTimeDataInterFace order by [id] desc ";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

TMemoryStream *MemoryStream = new TMemoryStream();

TJPEGImage *JpgImage = new TJPEGImage();

try

{

dynamic_cast<TBlobField*>(ADOQuery1->FieldByName("Picture"))->SaveToStream(MemoryStream);

MemoryStream->Position=0;

JpgImage->LoadFromStream(MemoryStream);

Image2->Picture->Assign(JpgImage);

}catch(...)

{

delete MemoryStream;

delete JpgImage;

}

delete MemoryStream;

delete JpgImage;

}

//---------------------------------------------------------------------------

void __fastcall TForm1::Button7Click(TObject *Sender)

{

AnsiString Sql = "select * from Tbl_RealTimeDataInterFace order by [id] desc ";

ADOQuery1->Close();

ADOQuery1->SQL->Clear();

ADOQuery1->SQL->Text = Sql;

ADOQuery1->Open();

TStream *Stream1;

TJPEGImage *Pjp = new TJPEGImage();

try

{

Stream1=ADOQuery1->CreateBlobStream(ADOQuery1->FieldByName("Picture"), bmRead); //Picture是存放jpeg内容的字段,它的类型一定要用image

Pjp->LoadFromStream(Stream1);

dbimg_1->Picture->Bitmap->Assign(Pjp); // dbimg_1是TDBImage组件,它的 DateSource,和 FieldName属性要空着

Image2->Picture->Bitmap->Assign(Pjp);

delete Stream1;

}

__finally

{

ADOQuery1->Close();

delete Pjp;

}

}

//------------------------- 清空图片 --------------------------------------------------

void __fastcall TForm1::Button3Click(TObject *Sender)

{

Image2->Picture->Assign(NULL);

}

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