DTS - Vbscript transformation

Try this

Function Main()
dim zipcode

  ZipCode = DTSDataSource("zipcode")
  ZipCode = string(5-len(ZipCode),"0") & ZipCode
  DTSDestination("zipcode") = ZipCode
  Main = DTSTransformStat_OK

End Function

Sorry, that should have read:
 (difference in DTSSource line)

Function Main()
dim zipcode

  ZipCode = DTSSource("zipcode")
  ZipCode = string(5-len(ZipCode),"0") & ZipCode
  DTSDestination("zipcode") = ZipCode
  Main = DTSTransformStat_OK

End Function

This looks great, but I'm getting errors, apparently
on NULL's  in the source zipcodes.  

as a guss, try

Function Main()
dim zipcode

  ZipCode = DTSSource("zipcode")
  If Not Null(ZipCode) then
    ZipCode = string(5-len(ZipCode),"0") & ZipCode
  Else
    ZipCode = "" ' Or any "Default" value you prefer
  End If
  DTSDestination("zipcode") = ZipCode
  Main = DTSTransformStat_OK
End Function


This will put any entries in your source db in with an empty string in your destination table.

Hope this helps.

Does the code above prefix every zipcode with
'O'? This wouldn't work if the zipcode does not have
zero in the first position.

as an afterthought,
the lines

  Else
    ZipCode = Null
  End if

should work if you are allowing nulls in your destination table, but as a rule I never allow nulls in my db's unless there is no logical concept of a default value. For example, a field called BirthDay could have a default value of Null because if I don't know the true value, then some other value is more wrong than null, but
a Field of Name I would prefer an empty string ("" in vb, or '' in tsql) to Null.

I am not familiar with US zip codes (assuming these are us?) but if all of the zip codes you are getting are supposed to be 5 digits long, this will put 0's in front of any other number, and leave you with zip codes all of 5 digits long. for examples the following would result.

Source        Destination
1243             01234
12345            12345
11               00011
9                00009
10000            10000


If you have zip codes that 'could' be shorter than 5 digits, then you may need to change the column properties in the Excel spreadsheet first to say a text, then manually adjust those zip codes which need a zero put on the front of them.

I'll try out your suggestions and back get to you.
No, actually the NULLS are on the input file, appear
to be blank records - I'll have to look at that.

Doesn't work. An error "invalid use of NULL" occurs,even when I eliminate most everything but
the  "ZipCode = string(5-len(ZipCode),"0") & ZipCode" statement.  
Can I stop processing when it gets to the NULL
records toward the end of the spreadsheet,
like the traditional "end of file" processing?

try using a string function to convert your dtssource data

In oracle you can use to_char. I dont know the equivalent in vb.

I think it is ctsr in vb.

Modify your line
ZipCode = DTSSource("zipcode")
into
ZipCode = DTSSource("zipcode").Value

Explanation:
VBScript is not really typed, and therefore has problems with the default properties

We were able to avoid the problem by redefining
the column in excel to TEXT.  The approach
described here will be useful in the future!