Pass a vbscript String list to a SQL "in"operator

Question

In the vb script I have a select statement I am trying to pass a string value with an undetermined length to a SQL in operator the below code works but allows for SQL injection.

I am looking for a way to use the ADO createParameter method. I believe the different ways I have tried are getting caught up in my data type (adVarChar, adLongChar, adLongWChar)

    Dim studentid 
studentid = GetRequestParam("studentid")

Dim rsGetData, dbCommand
    Set dbCommand = Server.CreateObject("ADODB.Command")
    Set rsGetData = Server.CreateObject("ADODB.Recordset")
    dbCommand.CommandType = adCmdText
    dbCommand.ActiveConnection = dbConn
dbCommand.CommandText = "SELECT * FROM students WHERE studentID in (" & studentid & ")"
Set rsGetData = dbCommand.Execute()

I have tried

Call addParameter(dbCommand, "studentID", adVarChar, adParamInput, Nothing, studentid)

which gives me this error ADODB.Parameters error '800a0e7c' Problems adding parameter (studentID)=('SID0001','SID0010') :Parameter object is improperly defined. Inconsistent or incomplete information was provided.

I have also tried

Call addParameter(dbCommand, "studentID", adLongVarChar, adParamInput, Nothing, studentid)

and

    Dim studentid 
studentid = GetRequestParam("studentid")

Dim slength
slength = Len(studentid)
response.write(slength)

Dim rsGetData, dbCommand
    Set dbCommand = Server.CreateObject("ADODB.Command")
    Set rsGetData = Server.CreateObject("ADODB.Recordset")
    dbCommand.CommandType = adCmdText
    dbCommand.ActiveConnection = dbConn
dbCommand.CommandText = "SELECT * FROM students WHERE studentID in (?)"
    Call addParameter(dbCommand, "studentID", adVarChar, adParamInput, slength, studentid)
Set rsGetData = dbCommand.Execute()

both of these options don't do anything... no error message and the SQL is not executed.

Additional information:

studentid is being inputted through a HTML form textarea. the design is to be able to have a user input a list of student id's (up to 1000 lines) and perform actions on these student profiles. in my javascript on the previous asp I have a function that takes the list and changes it into a comma delimited list with '' around each element in that list.

Answer 1

What does your addParameter() function do? I don't see that anywhere in your code.

You should be able to create and add your string param like so:

With dbCommand
    .Parameters.Append .CreateParameter(, vbString, , Len(studentid), studentid)
End With

(Small hack here. vbString has the same value as adBSTR. You'll find that the VarType of all VB "types" have matching ADO counterparts.)

Type       VarType (VBScript)  DataTypeEnum (ADO)  Value
---------  ------------------  ------------------  -----
Integer    vbInteger           adSmallInt, 2-byte      2
Long       vbLong              adInteger, 4-byte       3
Single     vbSingle            adSingle                4
Double     vbDouble            adDouble                5
Currency   vbCurrency          adCurrency              6
Date       vbDate              adDate                  7
String     vbString            adBSTR                  8
Object     vbObject            adIDispatch             9
Error      vbError             adError                10
Boolean    vbBoolean           adBoolean              11
Variant    vbVariant           adVariant              12
Byte       vbByte              adUnsignedTinyInt      17

---

Edit: Looks like Joel has a good solution for you. I didn't realize IN isn't compatible with ADO parameterized queries. I think something like the following would work, but you probably wouldn't want to do it with (potentially) 1000 ID's.

' Create array from student IDs entered...
a = Split(studentid, ",")

' Construct string containing proper number of param placeholders. Remove final comma.
strParams = Replace(String(UBound(a) - 1, "?"), "?", "?,")
strParams = Left(strParams, Len(strParams) - 1)

With dbCommand
    .CommandText = "select * from students where studentID in (" & strParams & ")"
    Set rsGetData = .Execute(, a)
End With

Answer 2

Classic ASP does not have good support for this. You need to fall back to one of the alternatives discussed here:

http://www.sommarskog.se/arrays-in-sql-2005.html

That article is kind of long, but in a good way: it's considered by many to be the standard work on this subject.

It also just so happens that my preferred option is not included in that article. What I like to do is use a holding table for each individual item in the list, such that each item uses an ajax request to insert or remove it from the holding table the moment the user selects or de-selects it. Then I join to that table for my list, so that you end up with something like this:

SELECT s.* 
FROM students s
INNER JOIN studentSelections ss on s.StudentID = ss.StudentID
WHERE ss.SessionKey = ?

Answer 3

Using IN with a Parameterised Query isn't Hard

Posting this here in relation to another question that was marked as a duplicate of this one.

This isn't as difficult as you think, the adCmdText query just needs to the placeholders in the query to match the number of parameters and their ordinal position and it will work with any number of parameters you pass into an IN statement.

Here is a quick example using the AdventureWorks example database in SQL Server. We use an Array to store the id of each Person.Contact record we wish to filter out using IN than build the parameters dynamically based on that array before executing the ADODB.Command.

Note: The source of the array is not important it could be a string list which is Split() into an Array or just an Array() call (like the one used in this example).

<%
Option explicit
%>
<!-- #include virtual = "/config/data.asp" -->
<%
Dim cmd, rs, sql, data, rows, row
'Our example parameters as an Array for the IN statement.
Dim ids: ids = Array(2, 5, 10)
Dim id

sql = ""
sql = sql & "SELECT [FirstName], [LastName] " & vbCrLf
sql = sql & "FROM Person.Contact " & vbCrLf
sql = sql & "WHERE [ContactId] IN (?, ?, ?) " & vbCrLf
sql = sql & "ORDER BY [LastName], [FirstName]" & vbCrLf

Set cmd = Server.CreateObject("ADODB.Command")
With cmd
  .ActiveConnection = conn_string
  .CommandType = adCmdText
  .CommandText = SQL
  'Loop through the Array and append the required parameters.
  For Each id in ids
    Call .Parameters.Append(.CreateParameter("@id" & id, adInteger, adParamInput, 4))
    .Parameters("@id" & id).Value = id
  Next
  Set rs = .Execute()
  'Output the Recordset to a 2-Dimensional Array
  If Not rs.EOF Then data = rs.GetRows()
  Call rs.Close()
End With
Set cmd = Nothing

If IsArray(data) Then
  rows = UBound(data, 2)
  For row = 0 To rows
    Call Response.Write("<p>" & data(0, row) & " " & data(1, row) & "</p>" & vbCrLf)
  Next
End If
%>

Output:

<p>Catherine Abel</p>
<p>Pilar Ackerman</p>
<p>Ronald Adina</p>

Worth noting this example shows the explicit way of writing the parameter code for an elegant approach to the problem see the second solution in @Bond's answer.

Answer 4

After reading through the article that was provided by Joel and the answer that All Blond provided this is the solution that ended up working for me.

Dim studentid
studentid = GetRequestParam("studentid")

Dim splitStudentid, x
splitStudentid = Split(studentid,",")

for x=0 to Ubound(splitStudentid)
Dim rsGetData, dbCommand, originSID
Set dbCommand = Server.CreateObject("ADODB.Command")
Set rsGetData = Server.CreateObject("ADODB.Recordset")
dbCommand.CommandType = adCmdText
dbCommand.ActiveConnection = dbConn
dbCommand.CommandText = "SELECT * FROM students WHERE studentID=?"
Call addParameter(dbCommand, "studentID", adVarChar, adParamInput, 35, splitStudentid(x))
Set rsGetData = dbCommand.Execute()

If (NOT rsGetData.EOF) Then 
    originSID = rsGetData.Fields(0)
    //additional code
End If
next

I found that there was no elegant way to use the "in" operator in my code. I also decided against a Stored Procedure as it is a simple query though I agree

ALSO I realize that addParameter is a Function my company uses internally so below is an additional solution that works also works but is not my companies preference.

    Dim studentid
studentid = GetRequestParam("studentid")

Dim splitStudentid, x
splitStudentid = Split(studentid,",")

for x=0 to Ubound(splitStudentid)
Dim rsGetData, dbCommand, originSID
Set dbCommand = Server.CreateObject("ADODB.Command")
Set rsGetData = Server.CreateObject("ADODB.Recordset")
dbCommand.CommandType = adCmdText
dbCommand.ActiveConnection = dbConn
dbCommand.CommandText = "SELECT * FROM students WHERE studentID=?"
Set rsGetData = dbCommand.Execute(, Array(splitStudentid(x)))

If (NOT rsGetData.EOF) Then 
    originSID = rsGetData.Fields(0)
    //additional code
End If
next

Answer 5

Try to add to your code following(assuming that StudentID is numeric)

 dim outputArray,x,compareArray
 outputArray=split(inputText,",")
 for each x in outputArray
  If IsNumeric(x) Then
      if len(compareArray)>1  and cInt(x)>0 then
         compareArray=compareArray&"," & cInt(x)
      else
          compareArray=cInt(x)
      end if
   else
     ' throw some log entry or do something for you to know that someone try
   end if
 next

and then do all your Db connection set etc up to this point where you use this new string of integers:

  dbCommand.CommandText = "SELECT * FROM students WHERE studentID in (" & compareArray &")"

and this will safeguard you from anyone use your StudentId list for SQL injection. I would rather use Store procedure and user-defined table types but ...

In any case if it is not numeric then it must have some parameter like length or complexity which you can use to verify that value has not been compromised using regular expression for example for limiting what can be in that value; but idea of the looping through and verifying values remain the same.