MS Access Update Query based on Index Number and o

I have a function I am trying to do for a database I am working on for my job. I'm not the most proficient with Access so I apologize if I am not wording this in the best way.

What I am trying to do is create a query/macro that will mimic the behavior as shown

and result into this:

The logic is as follows

1) for each record - take the LEN of the string in StdName. Take that number of characters and UPDATE that to the Name field. The remaining characters after the LEN is moved to the 'SuffixString' Field

2)for each record - count the number of occurrences of the string in the 'StdName' field for any records ON OR BEFORE the index number and UPDATE the 'Name' field with whatever is in there already and concatenate with "_n" where n is the occurence

example: index 1 - has one occurrence of 'Car1' in the StdName Field between record 1 and record 1. index 1 'Name' is changed to Car1_1

example: index 2 - has two occurrences of 'Car1' in the StdName Field between record 1 and record 2. index 2 'Name' is changed to Car1_2

example: index 6 - has one occurrence of 'Car3" in the StdName Field between record 1 and record 6. index 6 'Name' is changed to Car3_1

Can something like this be done with an access query? I've never developed in Access before and my boss really wants to see this function kept inside access instead of being moved in an out of excel.

(I have step 1 setup this way to later put in logic where StdName does not match Name. example: "Car1_1" for Name and StdName "Car2". I realize I could just Concatenate StdName with the function in step 2 in this example i described, but I have a real world purpose of doing it this way)

This will be done on an MDB format

Thank you

You can use my RowCounter function:

SELECT RowCounter(CStr([Index]),False,[StdName])) AS RowID, *
FROM YourTable
WHERE (RowCounter(CStr([Index]),False) <> RowCounter("",True));

or:

SELECT [StdName] & "_" & CStr(RowCounter(CStr([Index]),False,[StdName]))) AS RankedName, *
FROM YourTable
WHERE (RowCounter(CStr([Index]),False) <> RowCounter("",True));

Edit - to update:

UPDATE s_before
SET [Name] = [StdName] & "_" & CStr(RowCounter(CStr([Index]),False,[StdName])) 
WHERE (RowCounter(CStr([Index]),False) <> RowCounter("",True));

Code:

Public Function RowCounter( _
  ByVal strKey As String, _
  ByVal booReset As Boolean, _
  Optional ByVal strGroupKey As String) _
  As Long

' Builds consecutive RowIDs in select, append or create query
' with the possibility of automatic reset.
' Optionally a grouping key can be passed to reset the row count
' for every group key.
'
' Usage (typical select query):
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable
'   WHERE (RowCounter(CStr([ID]),False) <> RowCounter("",True));
'
' Usage (with group key):
'   SELECT RowCounter(CStr([ID]),False,CStr[GroupID])) AS RowID, *
'   FROM tblSomeTable
'   WHERE (RowCounter(CStr([ID]),False) <> RowCounter("",True));
'
' The Where statement resets the counter when the query is run
' and is needed for browsing a select query.
'
' Usage (typical append query, manual reset):
' 1. Reset counter manually:
'   Call RowCounter(vbNullString, False)
' 2. Run query:
'   INSERT INTO tblTemp ( RowID )
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable;
'
' Usage (typical append query, automatic reset):
'   INSERT INTO tblTemp ( RowID )
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable
'   WHERE (RowCounter("",True)=0);
'
' 2002-04-13. Cactus Data ApS. CPH
' 2002-09-09. Str() sometimes fails. Replaced with CStr().
' 2005-10-21. Str(col.Count + 1) reduced to col.Count + 1.
' 2008-02-27. Optional group parameter added.
' 2010-08-04. Corrected that group key missed first row in group.

  Static col      As New Collection
  Static strGroup As String

  On Error GoTo Err_RowCounter

  If booReset = True Then
    Set col = Nothing
  ElseIf strGroup <> strGroupKey Then
    Set col = Nothing
    strGroup = strGroupKey
    col.Add 1, strKey
  Else
    col.Add col.Count + 1, strKey
  End If

  RowCounter = col(strKey)

Exit_RowCounter:
  Exit Function

Err_RowCounter:
  Select Case Err
    Case 457
      ' Key is present.
      Resume Next
    Case Else
      ' Some other error.
      Resume Exit_RowCounter
  End Select

End Function