Re: Help!!! IT'S THE BLOB...

From: mark tomlinson <marktoml_at_gdi.net>
Date: 1998/05/29
Message-ID: <356fbd94.157488666@newshost.us.oracle.com>#1/1

Here is one way to do it in VB...

'This is Important! Option Base must = 1 for this example to work
'otherwise the data retreived will be incorrect
Option Base 1

Private Sub Command1_Click()
' Create Table script
' create table testlraw ( c1 number primary key, name varchar2(100),
c2 number, c3 long raw);
' Max ChunkSize is < 32k

Const ChunkSize = 4096

Dim RawData() As Byte
Dim RawLength As Long
Dim Offset As Long     

Dim oev As rdoEnvironment
Dim odb As rdoConnection
Dim ody As rdoResultset   

' Establsh a connection

Set oev = rdoEnvironments(0)
oev.CursorDriver = rdUseOdbc
Set odb = oev.OpenConnection("", rdDriverNoPrompt, False, "DSN=V803-TEST;UID=SCOTT;PWD=TIGER;")
'This sql could be modifed to include a where condition, or you could
use the
'find/move methods of the ResultSet to position yourself on the
correct row for
'update...

Set ody = odb.OpenResultset("select name, c1, c2, c3 from testlraw for update", rdOpenDynamic, rdConcurRowVer)   

' Read the target file from disk

Open "D:\STAGE\TEST.ZIP" For Binary Access Read As #1 If ody.EOF = True Then
ody.AddNew
Else
ody.Edit
End If
' Establsh the length of the raw data and the number of chunks
required
RawLength = LOF(1)
Offset = 1
Do
  If Offset + ChunkSize <= RawLength Then

      ReDim RawData(ChunkSize)
  Else

      ReDim RawData(RawLength - Offset + 1)   End If
  Get #1, Offset, RawData()
  ody!c3.AppendChunk RawData()
  Offset = Offset + ChunkSize
Loop While Offset < RawLength
Close #1

ody!c2.Value = RawLength
ody!Name.Value = "TEST"
ody!c1.Value = 1

ody.Update

ody.Close

Set ody = odb.OpenResultset("select name, c1, c2, c3 from testlraw", rdOpenDynamic, rdConcurRowVer)

' Write the returned file out to disk

Open "D:\STAGE\f.zip" For Binary Access Write As #1

' Establsh the length of the raw data

' Note: RawLength = ody("c3").ColumnSize will always return -1 with
Oracle
' However, this may be valid on other vendor DBs -or- you can
' make use of the generic code that handles '-1' returns below
' to determine the column size on the fly
'RawLength = ody("c3").ColumnSize

' Note: It is expected that you store the length of the target column
' on upload both to speed up this process and to provide a checksum
RawLength = ody("c2").Value

Dim RawTemp As Variant
Offset = 1
If RawLength = -1 Then
  Do
    RawTemp = ody!c3.GetChunk(ChunkSize)     RawData() = RawTemp
    Put #1, Offset, RawData()
    Offset = Offset + LenB(RawTemp)
  Loop While LenB(RawTemp) = ChunkSize
Else
  Do
    RawData() = ody!c3.GetChunk(ChunkSize)     Put #1, Offset, RawData()
    Offset = Offset + ChunkSize
  Loop While Offset < RawLength
End If
Close #1

ody.Close
odb.Close
MsgBox "Done"

End Sub Received on Fri May 29 1998 - 00:00:00 CDT