Adodc connection string problem.

ok, so you can make it in several ways
First is creating three ODBC data sources (3 DSN) in your system and choosing which one will use in runtime
Second way in creating a DSN in run time. You can make it like this

' Registry API functions
Private Declare Function SQLConfigDataSource Lib "ODBCCP32.DLL" _
    (ByVal hwndParent As Long, ByVal fRequest As Long, _
    ByVal lpszDriver As String, _
    ByVal lpszAttributes As String) As Long
Private Declare Function RegCloseKey Lib "advapi32" _
    (ByVal hKey As Long) As Long
Private Declare Function RegOpenKeyEx Lib "advapi32" _
    Alias "RegOpenKeyExA" (ByVal hKey As Long, _
    ByVal lpSubKey As String, ByVal ulOptions As Long, _
    ByVal samDesired As Long, ByRef phkResult As Long) As Long
Private Declare Function RegQueryValueEx Lib "advapi32" _
    Alias "RegQueryValueExA" (ByVal hKey As Long, _
    ByVal lpValueName As String, ByVal lpReserved As Long, _
    ByRef lpType As Long, ByVal lpData As String, _
    ByRef lpcbData As Long) As Long

Const REG_SZ = 1
Const KEY_ALL_ACCESS = &H2003F
Const HKEY_CURRENT_USER = &H80000001

Const ODBC_ADD_DSN = 1      ' Add data source
Const ODBC_REMOVE_DSN = 3   ' Delete data source

'Create and delete DSN at runtime
Sub MakeDSN(ByVal sDSN As String, ByVal sDriver As String, _
    ByVal sDBFile As String, ByVal lAction As Long)

    Dim sAttributes As String
    Dim sDBQ As String
    Dim lngRet As Long
    Dim hKey As Long
    Dim regValue As String
    Dim valueType As Long
 
    ' query the Registry to check whether the DSN is already
installed
    ' open the key
    If RegOpenKeyEx(HKEY_CURRENT_USER, "Software\ODBC\ODBC.INI\" _
        & sDSN, 0, KEY_ALL_ACCESS, hKey) = 0 Then
        ' zero means no error => Retrieve value of "DBQ" key
        regValue = String$(1024, 0)
        ' Allocate Variable Space
        If RegQueryValueEx(hKey, "DBQ", 0, valueType, _
            regValue, Len(regValue)) = 0 Then
            ' zero means OK, so we can retrieve the value
            If valueType = REG_SZ Then
                sDBQ = Left$(regValue, InStr(regValue, vbNullChar)
 - 1)
            End If
        End If
        ' close the key
        RegCloseKey hKey
    End If
   
    ' Perform the action only if we're adding a DSN that doesn't
exist
    ' or removing and existing DSN
    If (sDBQ = "" And lAction = ODBC_ADD_DSN) Or _
        (sDBQ <> "" And lAction = ODBC_REMOVE_DSN) Then
       
        ' check that the file actually exists
        If Len(Dir$(sDBFile)) = 0 Then
            Err.Raise 53, , "Database file doesn't exist!"
        End If
        sAttributes = "DSN=" & sDSN & vbNullChar _
            & "DBQ=" & sDBFile & vbNullChar
        lngRet = SQLConfigDataSource(0&, lAction, sDriver,
sAttributes)
    End If
End Sub

Here 's an example to create a DSN, called "DSN Creation Test",
that points to a Access database:

sDriver = "Microsoft Access Driver (*.mdb)"
sName = "DSN Creation Test"
sFile = App.Path & "\MyDatabase.mdb"
MakeDSN sName, sDriver, sFile, ODBC_ADD_DSN

Don't worry if the code is very strong, just only try to probe it. It works fine.

Hope this will help you