Extract Oracle LONG to string in VBA

问题

I'm having trouble getting a field of LONG out of the database and into my Excel (VBA + ADO) application. I wonder if anyone could help?

Doing this has no effect at all (casting to a string, or not):

myString = dataset!long_field

I tried the GetChunk method, which is supposed to do what I'm hoping:

myString = CStr(dataset!long_field.GetChunk(1000))

This does get something, but it's not the data I'm expecting (it's usually some garbled mess). What's weird is that, if I try running this in the Immediate window, while I'm stepping through the code, I get something hopeful:

Debug.Print CStr(dataset!long_field.GetChunk(1000))
 e l l o  W o r l d !

I don't know why it (sort of) works in the Immediate window and not elsewhere. Also of note:

Oracle seems to be using some kind of 2-byte encoding, so there's the weird spacing
A chunk of the data from the beginning is missing; this should read "Hello World!"

My other plan of attack was to write a function on the database side to convert long to varchar2. Unfortunately, this also failed because the table I need to access is outside my schema and I don't have the appropriate grants to select the data from a function (Oracle complains that the table is not found).

So I'm kind of lost :( Any ideas?

回答1:

This works for me:

Debug.Print BinaryToString(RS.Fields("long_raw").Value)

Where "RS" is an ADO recordset containing query results and "BinaryToString" is as shown below.

Function BinaryToString(Binary)
  'Antonin Foller, http://www.motobit.com
  'Optimized version of a simple BinaryToString algorithm.

  Dim cl1, cl2, cl3, pl1, pl2, pl3
  Dim L
  cl1 = 1
  cl2 = 1
  cl3 = 1
  L = LenB(Binary)

  Do While cl1 <= L
    pl3 = pl3 & Chr(AscB(MidB(Binary, cl1, 1)))
    cl1 = cl1 + 1
    cl3 = cl3 + 1
    If cl3 > 300 Then
      pl2 = pl2 & pl3
      pl3 = ""
      cl3 = 1
      cl2 = cl2 + 1
      If cl2 > 200 Then
        pl1 = pl1 & pl2
        pl2 = ""
        cl2 = 1
      End If
    End If
  Loop
  BinaryToString = pl1 & pl2 & pl3
End Function

回答2:

Turns out that GetChunk does work: I did some sandbox testing and, while there's still the weird encoding, it does return all the data I want. As such, I don't know why the data is getting garbled in my main query; so my solution is to just use a function that gets the long data -- and decodes it -- and call this when needed, rather than including the data in the main query.

来源：https://stackoverflow.com/questions/7980483/extract-oracle-long-to-string-in-vba

标签

Oracle

excel

vba

blob

ado