SQL Server中的Image数据类型的操作

原文:SQL Server中的Image数据类型的操作

准备工作，在库Im_Test中建立一张表Im_Info，此表中有两个字段，分别为Pr_Id （INT），Pr_Info (IMAGE)，用来存储图形编号及图形信息。其语法如下：

CREATE TEALE Im_Info (

Pr_Id INT NULL ，

Pr_Info IMAGE NULL

) 



第一步: 往表中插入一条记录，并初始化PR_INFO字段。其语法如下：

INSERT INTO Im_Info VALUES （1 ，0xFFFFFFFF）

第二步往表中写入图形信息。其语法如下：

DECLARE @@ptrval varbinary(16)

SELECT @@ptrval = TEXTPTR(Pr_Info)

FROM Im_Info

WHERE Pr_Id = 1

WRITETEXT Im_Text.Im_Info

@@ptrval 0x624fd543fd…..



其中0x624fd543fd….. 为图形的十六进制数据，可以通过C 、Java等工具获得。

注意在写入图形信息前必须先将此数据库的 'select into/bulkcopy' 属性设置为 True ，其语法如下：

use master

exec sp_dboption Im_Test ,'select into/bulkcopy' ,True

C#读取Image数据类型：

（1）控制台应用程序下演示插入图片

public void InsertIMG()

        {

//将需要存储的图片读取为数据流

            FileStream fs = new FileStream(@"E:\c.jpg", FileMode.Open,FileAccess.Read);

            Byte[] btye2 = new byte[fs.Length];

            fs.Read(btye2 , 0, Convert.ToInt32(fs.Length));

            fs.Close();

           

            using (SqlConnection conn = new SqlConnection(sqlconnstr))

            {

                conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.Connection = conn;

                cmd.CommandText = "insert into T_Img(imgfile) values(@imgfile)";

                SqlParameter par = new SqlParameter("@imgfile", SqlDbType.Image);

                par.Value = bt;

                cmd.Parameters.Add(par);

int t=(int)(cmd.ExecuteNonQuery());

                if (t > 0)

                {

                    Console.WriteLine("插入成功");

                }

                conn.Close();

            }

        }

（2）控制台应用程序下读出并生成图片到物理位置

public void Read()

        {

            byte[] MyData = new byte[0];

            using (SqlConnection conn = new SqlConnection(sqlconnstr))

            {

                conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.Connection = conn;

                cmd.CommandText = "select * from T_img";

                SqlDataReader sdr = cmd.ExecuteReader();

                sdr.Read();

                MyData = (byte[])sdr["ImgFile"];//读取第一个图片的位流

                int ArraySize= MyData.GetUpperBound(0);//获得数据库中存储的位流数组的维度上限，用作读取流的上限

FileStream fs = new FileStream(@"c:\00.jpg", FileMode.OpenOrCreate, FileAccess.Write);

                fs.Write(MyData, 0, ArraySize);

                fs.Close();   //-- 写入到c:\00.jpg。

                conn.Close();

                Console.WriteLine("读取成功");//查看硬盘上的文件

            }

        }

（3）Web下picshow.aspx页将图片读取出来并写入到浏览器上呈现

public void Read()

    {

        byte[] MyData = new byte[0];

        using (SqlConnection conn = new SqlConnection(sqlconnstr))

        {

            conn.Open();

            SqlCommand cmd = new SqlCommand();

            cmd.Connection = conn;

            cmd.CommandText = "select * from T_img";

            SqlDataReader sdr = cmd.ExecuteReader();

            sdr.Read();

            MyData = (byte[])sdr["ImgFile"];

            Response.ContentType = "image/gif";

            Response.BinaryWrite(MyData);

            conn.Close();

            Response.Write("读取成功");

        }

（4）在web中可以如上picshow.aspx页面读取并显示图片，而真正引用该图片时如下示例

<img src="picshow.aspx" width="500" height="300" />

 （5）Winform下将图片写入到sql数据库image类型字段中的方法和以上方法基本一致，仅区别于可以利用多个对话框来帮助选取存储图片等，各个属性可以方便的利用上

（6）Winform下读取图片在picturebox控件中显示出来

方法一：利用MemoryStream 和System.Drawing.Image

public void Read()

        {

            byte[] MyData = new byte[0];

            using (SqlConnection conn = new SqlConnection(sqlconnstr))

            {

                conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.Connection = conn;

                cmd.CommandText = "select * from T_img";

                SqlDataReader sdr = cmd.ExecuteReader();

                sdr.Read();

                MyData = (byte[])sdr["ImgFile"];

MemoryStream mystream = new MemoryStream(MyData);

                //用指定的数据流来创建一个image图片

                System.Drawing.Image img = System.Drawing.Image.FromStream(mystream, true);

               

                System.Windows.Forms.PictureBox picbox = new PictureBox();

                picbox.Image = img;

                picbox.Left = 30;

                picbox.Top = 80;

                picbox.Width = 800;

                picbox.Height = 500;

                this.Controls.Add(picbox);

mystream.Close();

                conn.Close();

            }

        }

方法二：将流直接读取成图片并写入到物理位置，然后再行利用该图片呈现

void Read()

        {

            using (SqlConnection conn = new SqlConnection(sqlconnstr))

            {

                conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.Connection = conn;

                cmd.CommandText = "select * from T_img";

                SqlDataReader sdr = cmd.ExecuteReader();

                sdr.Read();

byte[] Image_img = (byte[])sdr["ImgFile"];

                if (Image_img.Length == 0)

                {

                    return;

                }

                int filelength = Image_img.Length;

                string imageName = "1.jpg";

                string myUrl = Environment.CurrentDirectory + "\\" + imageName;

                FileStream fs = new FileStream(myUrl, FileMode.OpenOrCreate,FileAccess.Write);

                BinaryWriter BW = new BinaryWriter(fs);

                BW.BaseStream.Write(Image_img, 0, filelength);

                BW.Flush();

                BW.Close();

                System.Windows.Forms.PictureBox picbox = new PictureBox();

               

                //为picbox添加图片方法一

                //picbox.ImageLocation = myUrl;

                //picbox.Width = 800;

                //picbox.Height = 300;

//为picbox添加图片方法二

                Bitmap bitmap = new Bitmap(myUrl);

                picbox.Width = 100;//bitmap.Width;

                picbox.Height = 80;//bitmap.Height;

                picbox.Image = (Image)bitmap;

                picbox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;

                picbox.Left = 20;

                picbox.Top = 30;

this.Controls.Add(picbox);

                conn.Close();

               

            }

        }