SQL Server中的Image数据类型的操作

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();
               
            }
        }