Read Image stored in Oracle using Long DataType - asp.net-mvc

Question

I want to read the image stored in Oracle Long datatype.
Number of images are stored in a remote Oracle database in a column with datatype long. I just need to retrieve those images and show them on my aspx page.
I could retrieve the image from database but when tried to caste it to byte array, it threw error that, string can not be converted to byte[]'.
Anybody have any suggestions on how to retrieve these images stored in long column in database.
byte[] signatureBlobReceived = cls_TBL_BROKER_BL.GetInstance().GetSignatureBlobFromAccountNumber_BL(strCRNnumber);
return File(signatureBlobReceived, "image/jpeg");
public byte[] GetSignatureBlobFromAccountNumber_BL()
{
object SignatureBlob = null;
Database db = DatabaseFactory.CreateDatabase("imageConnectionString");
DbCommand dbc = db.GetSqlStringCommand(ConfigurationSettings.AppSettings["signqry"].ToString());
dbc.CommandType = CommandType.Text;
SignatureBlob = db.ExecuteScalar(dbc);
byte[] array = Encoding.ASCII.GetBytes(Convert.ToString(SignatureBlob));
string aa = string.Empty;
return array;
}
Query used is:
<add key="signqry" value="SELECT image FROM table1"/> `

Answer 1

Try this (odp.net)
string connStr = "User Id=user;Password=pwd;Data Source=mySID;";
OracleConnection _conn = new OracleConnection(connStr);
_conn.Open();
string sel = #"select long_raw_col from long_raw_test";
OracleCommand cmd = new OracleCommand(sel, _conn);
cmd.InitialLONGFetchSize = 5000;
OracleDataReader reader = cmd.ExecuteReader();
int rows = 0;
// loop through rows from table
while (reader.Read())
{
rows++;
byte[] buf = new byte[5000];
long bytesRead = reader.GetBytes(reader.GetOrdinal("long_raw_col"), 0, buf, 0, 5000);
FileStream fs = new FileStream("C:\\test\\test_long" + rows + ".dat", FileMode.Create);
fs.Write(buf, 0, (int)bytesRead);
fs.Close();
Console.WriteLine("Row " + rows + ": Read " + bytesRead + " bytes from table, see test_long" + rows + ".dat");
}
This example just reads the long raw data from Oracle into a byte array, then outputs to a file. Note the InitalLONGFetchSize > 0.

Answer 2

I use this class :my database is informix and the images are stored in Byte type .Hope this can help you.
public class MyPhoto
{
public static Stream RetrievePhoto()
{
DBConnection DAL_Helper = new DBConnection(ConfigurationSettings.AppSettings["connection"].ToString());
Byte[] myByteBuff;
Stream myImgStream;
string qry = "----------";
DataTable dt = DAL_Helper.Return_DataTable(qry);
try
{
if (dt.Rows.Count > 0)
{
if (!string.IsNullOrEmpty(dt.Rows[0][0].ToString()))
{
myByteBuff = (Byte[])((object)(dt.Rows[0][0]));
myImgStream = new MemoryStream(myByteBuff);
}
else
{
myImgStream = RetrievePhotoNoProfile();
}
}
else
{
myImgStream = RetrievePhotoNoProfile();
}
}
catch (Exception ex)
{
myImgStream = RetrievePhotoNoProfile();
}
return myImgStream;
}
public static byte[] StreamToByteArray(Stream stream)
{
if (stream is MemoryStream)
{
return ((MemoryStream)stream).ToArray();
}
else
{
return ReadFully(stream);
}
}
public static byte[] ReadFully(Stream input)
{
byte[] buffer = new byte[input.Length];
using (MemoryStream ms = new MemoryStream())
{
int read;
while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
{
ms.Write(buffer, 0, read);
}
return ms.ToArray();
}
}
private static Stream RetrievePhotoNoProfile()
{
string noprofileimgPath = HttpContext.Current.Server.MapPath("~/images/noprofile.png");
System.IO.FileStream fs = new System.IO.FileStream(noprofileimgPath, System.IO.FileMode.Open, FileAccess.Read);
byte[] ba = new byte[fs.Length];
fs.Read(ba, 0, (int)fs.Length);
Stream myImgStream = new MemoryStream(ba);
fs.Close();
return myImgStream;
}
public static Image byteArrayToImage(byte[] byteArrayIn)
{
MemoryStream ms = new MemoryStream(byteArrayIn);
Image returnImage = Image.FromStream(ms);
return returnImage;
}
}