How can I retrieve a LONG data type using ADO

Question

In VB I am using an ADODB object to retrieve data from an Oracle table that has a LONG data type column...
specifically: SELECT TRIGGER_BODY FROM USER_TRIGGERS WHERE TRIGGER_NAME = 'MYTRIGGER'
I have tried using the GETCHUNK method but it only returns the first 150 or so characters no matter how
many times I call it???? here is the sample code I'm using........
Dim Cn As ADODB.Connection, Rs As ADODB.Recordset, SQL As String
Dim sChunk() As Byte
Set Cn = New ADODB.Connection
Set Rs = New ADODB.Recordset
Cn.CursorLocation = adUseServer
Cn.Open "Provider=OraOLEDB.Oracle.1;Password=hrzadmin;Persist Security
Info=True;UserID=hadmin;Data Source=xxx.local"
SQL = "SELECT trigger_body from user_triggers where trigger_name = 'MYTRIGGER'"
Rs.Open SQL, Cn, adOpenStatic, adLockReadOnly
Debug.Print Rs!trigger_name
Debug.Print Rs!trigger_body
sChunk = rs.Fields("trigger_body").GetChunk(500)
Debug.Print sChunk

Answer 1

I have a similar code which works for chunk size >400,
The image I am trying to retrieve is huge so the chunksize is also more.
Did you try with any non meta table?
For your reference I am pasting my application code below.
Hope it helps.
--Jagriti
Private Sub cmdGetImage_Click()
Dim bytchunk() As Byte 'variable to store binary data
Dim destinationFileNum As Integer 'variable for filenumber
'recordset for fetching Product Image for the product selected form the list
Dim recProductImage As New ADODB.Recordset
Dim offset As Long
Dim totalsize As Long
Dim roundTrips As Long
'variables used in calculation of time taken to fetch the image
Dim startTime As Currency, EndTime As Currency, time As Currency, Freq As Currency
Dim i As Integer 'counter variable
i = 0
On Error GoTo ErrorText 'redirect to error handler
'** Step 1 **'
'validating if product is selected from the list
If cboSelectProduct.Text = "" Then
MsgBox "Select product from the list!"
Exit Sub
End If
'** Step 2 **'
'validating if "optChunk" optionbox is selected then
'"txtChunksize" textbox should contain a value
If optchunk.Value = True Then
'validate if chunksize value is null
If txtChunkSize.Text = "" Then
MsgBox "Enter value for chunksize "
Exit Sub
End If
'validating that the chunk size entered should be a positive value
If CInt(txtChunkSize.Text) < 1 Then
MsgBox "ChunkSize value should be positive!"
Exit Sub
End If
End If
'** Step 3 **'
'open image column from product_information table using m_Oracon connection
recProductImage.Open "SELECT product_image FROM product_information " & _
" WHERE product_id =" & cboSelectProduct.ItemData(cboSelectProduct.ListIndex) _
, m_Oracon, adOpenStatic _
, adLockOptimistic, adCmdText
'check if product image exists for the product selected
If Not IsNull(recProductImage!product_image) Then
'setting mouse pointer on the form "frmChunkSize" to wait state
frmChunkSize.MousePointer = vbHourglass
'** Step 4 **'
'assigning "desitinationFileNum" variable to next file number
'available for use
destinationFileNum = FreeFile
'allocates a buffer for I/O to the temporary file "tempImage.bmp"
'at the current application path
Open App.Path & "\tempImage.bmp" For Binary As destinationFileNum
'** Step 5 **'
'Get the frequency of internal timer in Freq variable
QueryPerformanceFrequency Freq
'start the timer
QueryPerformanceCounter startTime
'clear "imgProduct" imagebox
imgProduct.Picture = LoadPicture("")
'** Step 6 **
If optValue.Value = True And optchunk.Value = False Then
'** Step 7 **
'using ADO Value property
bytchunk = recProductImage("product_image").Value
'appending byte arrary data to the temporary file
Put destinationFileNum, , bytchunk
'displaying "No. of Round Trips" in a label to 1
lblRoundTrips = 1
ElseIf optchunk.Value = True Then
'** Step 8 **
'converting the value entered "txtChunkSize" textbox to long
'and assigning it to chunksize variable
m_chunksize = CLng(txtChunkSize.Text)
'assigning the actual size of the image retrieved to a variable
totalsize = recProductImage("product_image").ActualSize
'calculating and assigning the "No. of Round Trips" to a variable
roundTrips = totalsize / m_chunksize
'in case fragment of data left, incrementing roundtrips by 1
If (totalsize Mod m_chunksize) > 0 Then
roundTrips = roundTrips + 1
End If
'In this loop the image is retrieved in terms of chunksize
'and appended to the temporary file
Do While offset < totalsize
'** Step 9 **
'retrieving product_image from the recordset, in chunks of bytes
bytchunk = recProductImage("product_image").GetChunk(m_chunksize)
offset = offset + m_chunksize
'appending byte arrary data to the temporary file
Put destinationFileNum, , bytchunk
Loop
'displaying "No. of Round Trips" in a label
lblRoundTrips = roundTrips
End If
'** Step 10 **'
'stop the timer after image retrieval is done
QueryPerformanceCounter EndTime
'close the opened file handle
Close destinationFileNum