[VB.NET] สอบถามการ Select ข้อมูล Blob จาก Oracle โดยมีปัญหาไม่สามารถ query ได้เหมือนข้อมูลปกติ

Imports System
Imports System.Data
Imports Oracle.DataAccess.Client
Imports Oracle.DataAccess.Types
Imports System.IO
Imports System.Text

'Step 1
' Connect to database
' Note: Modify User Id, Password, Data Source as per your database setup
Dim constr As String = "User Id=Scott;Password=tiger;Data Source=orcl9i"
Dim con As OracleConnection = New OracleConnection(constr)
con.Open()
Console.WriteLine("Connected to database!")

' Step 2

' Note: Modify the Source and Destination location
' of the image as per your machine settings
Dim SourceLoc As String = "D:/Images/photo.jpg"
Dim DestinationLoc As String = "D:/Images/TestImage.jpg"

' provide read access to the file
Dim Fs As FileStream = New FileStream(SourceLoc,
                       FileMode.Open, FileAccess.Read)

' Create a byte array of file stream length
Dim ImageData As Byte()
ReDim imagedata(fs.Length)

'Read block of bytes from stream into the byte array
fs.Read(ImageData, 0, System.Convert.ToInt32(fs.Length))

'Close the File Stream
fs.Close()

' Step 3
' Create Anonymous PL/SQL block string
Dim block As String =
   " BEGIN " & _
   " INSERT INTO testblob (id, photo) VALUES (100, :1) ;" & _
   " SELECT photo into :2 from testblob WHERE id = 100 ;" & _
   " end ;"

' Set command to create Anonymous PL/SQL Block
Dim cmd As OracleCommand = New OracleCommand()
cmd.CommandText = block
cmd.Connection = con


' Since executing an anonymous PL/SQL block, setting the command type
' as Text instead of StoredProcedure
cmd.CommandType = CommandType.Text

' Step 4
' Setting Oracle parameters

' Bind the parameter as OracleDbType.Blob
' to command for inserting image
Dim param As OracleParameter = cmd.Parameters.Add("blobtodb", OracleDbType.Blob)
param.Direction = ParameterDirection.Input

' Assign Byte Array to Oracle Parameter
param.Value = ImageData


' Bind the parameter as OracleDbType.Blob
' to command for retrieving the image
Dim param2 As OracleParameter = cmd.Parameters.Add("blobfromdb", OracleDbType.Blob)
param2.Direction = ParameterDirection.Output


' Step 5
' Execute the Anonymous PL/SQL Block
' The anonymous PL/SQL block inserts the image to the database and then retrieves
' the images as an output parameter
cmd.ExecuteNonQuery()
Console.WriteLine("Image file inserted to database from "+ SourceLoc)


' Step 6
' Save the retrieved image to the DestinationLoc in the file system
' Create a byte array
Dim byteData As Byte()
Dim Paramvalue As OracleBlob
Paramvalue = cmd.Parameters(1).Value

' fetch the value of Oracle parameter into the byte array
byteData = CType((Paramvalue.Value), Byte())

' get the length of the byte array
Dim ArraySize As Integer = New Integer()
ArraySize = byteData.GetUpperBound(0)

' Write the Blob data fetched from database to the filesystem at
' the destination location
Dim fs1 As FileStream = New FileStream(DestinationLoc, 
                                       FileMode.OpenOrCreate, FileAccess.Write)
fs1.Write(byteData, 0, ArraySize)
fs1.Close()

Console.WriteLine("Image saved to " + DestinationLoc + " successfully !")
Console.WriteLine("")
Console.WriteLine("***********************************************************")

Console.WriteLine("Before running this application again, execute 'Listing 1' "
Console.WriteLine("given in 'Create Database Objects' section in the How-to.")
Console.WriteLine("***********************************************************")

Imports System.Data
Imports System.Data.OracleClient

Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    End Sub

    Protected Sub btnUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
        Me.pnlForm.Visible = False

        If Me.fUpload.HasFile = False Or Me.txtName.Text = "" Then
            Me.lblStatus.Text = "Please input Name and Chooes File."
        Else

            '*** Read Binary Data ***'
            Dim imbByte(fUpload.PostedFile.InputStream.Length) As Byte
            fUpload.PostedFile.InputStream.Read(imbByte, 0, imbByte.Length)

            '*** MimeType ***'
            Dim ExtType As String = System.IO.Path.GetExtension(fUpload.PostedFile.FileName).ToLower()
            Dim strMIME As String = Nothing
            Select Case ExtType
                Case ".gif"
                    strMIME = "image/gif"
                Case ".jpg", ".jpeg", ".jpe"
                    strMIME = "image/jpeg"
                Case ".png"
                    strMIME = "image/png"
                Case Else
                    Me.lblStatus.Text = "Invalid file type."
                    Exit Sub
            End Select

            '*** Insert to Database ***'
            Dim objConn As New OracleConnection
            Dim strConnString, strSQL As String

			strConnString = "Data Source=TCDB;User Id=myuser;Password=mypassword;"

            strSQL = "INSERT INTO files (Name,FilesName,FilesType) " & _
            " VALUES " & _
            " (:sName,:sFilesName,:sFilesType)"
            objConn.ConnectionString = strConnString
            objConn.Open()

            Dim objCmd As New OracleCommand(strSQL, objConn)
            objCmd.Parameters.Add(":sName", OracleType.VarChar).Value = Me.txtName.Text
            objCmd.Parameters.Add(":sFilesName", OracleType.Blob).Value = imbByte
            objCmd.Parameters.Add(":sFilesType", OracleType.VarChar).Value = strMIME
            objCmd.ExecuteNonQuery()

            objConn.Close()
            objConn = Nothing

            Me.lblStatus.Text = "File Upload Successfully. Click <a href='ListPicture.aspx'>here</a> to view."
        End If
    End Sub

End Class