C#操作Oracle BLOB字段的写入读取方法

1.写入BLOB

string file_name = "D:\\20080523.jpg";
string conn_str = "Provider=OraOLEDB.Oracle.1;Password=agoodjob;Persist Security Info=True;User ID=ams;Data Source=ims;Extended Properties=";//Provider必須用OraOLEDB.Oracle.1
OleDbConnection cn = new OleDbConnection(conn_str);
cn.Open();

OleDbCommand cmd = new OleDbCommand("UPDATE BLOB SET PHOTO = ? ",cn);
cmd.Parameters.Add("PHOTO",OleDbType.Binary);

FileStream fs = new FileStream(file_name, FileMode.OpenOrCreate, FileAccess.Read);
byte[] MyData= new byte[fs.Length];
fs.Read(MyData, 0, System.Convert.ToInt32(fs.Length));
fs.Close();

cmd.Parameters["PHOTO"].Value = MyData;
try
{
int result = cmd.ExecuteNonQuery();
if(result<1)
{
OleDbCommand cmd1 = new OleDbCommand(" INSERT INTO BLOB (PHOTO) VALUES ( ? )",cn);
cmd1.Parameters.Add("PHOTO",OleDbType.Binary);
cmd1.Parameters["PHOTO"].Value = MyData;
result = cmd1.ExecuteNonQuery();
}
}
catch(Exception e1)
{
Page.RegisterStartupScript("","<script language='javascript'>alert('"+e1.Message+"')</script>");
}
finally
{
cn.Close();
}

2.读取BLOB

string conn_str = "Provider=OraOLEDB.Oracle.1;Password=agoodjob;Persist Security Info=True;User ID=ams;Data Source=ims;Extended Properties=";//Provider必須用OraOLEDB.Oracle.1

OleDbDataAdapter da = new OleDbDataAdapter();
DataSet ds = new DataSet();
OleDbConnection conn = new OleDbConnection(conn_str);
OleDbCommand cmd = new OleDbCommand("SELECT PHOTO FROM WEB_DB.USERS WHERE USER_ID = 1", conn);
da.SelectCommand = cmd;
cmd.Connection.Open();
da.Fill(ds);

byte[] img = new byte[0];
DataRow dr;
dr = ds.Tables[0].Rows[0];

if (!ds.Tables[0].Rows[0]["PHOTO"].ToString().Equals(""))
{
img = (byte[])dr["PHOTO"];
}

Response.ContentType= "image/*";
Response.BinaryWrite (img);

conn.Close();