Add unique number to excel datasheet using VBA - vba

Question

I have two columns of numbers, together they will be unique (composite key). I would like to create an unique ID number (third column) similar to how MS Access would use a primary key. I would like to do this in VBA but I am stuck on how to do it.
My VBA in excel isn't very good so hopefully you can see what I've started to attempt. it may be completely wrong... I don't know?
I don't know how to make the next concatenation and I am unsure about how to go down to the next row correctly.
Sub test2()
Dim var As Integer
Dim concat As String
concat = Range("E2").Value & Range("F2").Value
var = 1
'make d2 activecell
Range("D2").Select
Do Until concat = ""
'if the concat is the same as the row before we give it the same number
If concat = concat Then
var = var
Else
var = var + 1
End If
ActiveCell.Value = var
ActiveCell.Offset(0, 1).Select
'make the new concatination of the next row?
Loop
End Sub
any help is appreciated, thanks.

Answer 1

Give the code below a try, I've added a loop which executes for each cell in the E Column. It checks if the concat value is the same as the concat value in the row above and then writes the id to the D cell.
Sub Test2()
Dim Part1 As Range
Dim strConcat As String
Dim i As Long
i = 1
With ThisWorkbook.Worksheets("NAME OF YOUR SHEET")
For Each Part1 In .Range(.Cells(2, 5), .Cells(2, 5).End(xlDown))
strConcat = Part1 & Part1.Offset(0, 1)
If strConcat = Part1.Offset(-1, 0) & Part1.Offset(-1, 1) Then
Part1.Offset(0, -1).Value = i
Else
i = i + 1
Part1.Offset(0, -1).Value = i
End If
Next Part1
End With
End Sub

Answer 2

Something like this should work, this will return a Unique GUID (Globally Unique Identifier):
Option Explicit
Sub Test()
Range("F2").Select
Do Until IsEmpty(ActiveCell)
If (ActiveCell.Value <> "") Then
ActiveCell.Offset(0, 1).Value = CreateGUID
End If
ActiveCell.Offset(1, 0).Select
Loop
End Sub
Public Function CreateGUID() As String
CreateGUID = Mid$(CreateObject("Scriptlet.TypeLib").GUID, 2, 36)
End Function

Answer 3

If you walk down column D and examine the concatenated values from column E and F with the previous row, you should be able to accomplish your 'primary key'.
Sub priKey()
Dim dcell As Range
With Worksheets("Sheet12")
For Each dcell In .Range(.Cells(2, 4), .Cells(Rows.Count, 5).End(xlUp).Offset(0, -1))
If LCase(Join(Array(dcell.Offset(0, 1).Value2, dcell.Offset(0, 2).Value2), ChrW(8203))) = _
LCase(Join(Array(dcell.Offset(-1, 1).Value2, dcell.Offset(-1, 2).Value2), ChrW(8203))) Then
dcell = dcell.Offset(-1, 0)
Else
dcell = Application.Max(.Range(.Cells(1, 4), dcell.Offset(-1, 0))) + 1
End If
Next dcell
End With
End Sub

Answer 4

You could use collections as well.
Sub UsingCollection()
Dim cUnique As Collection
Dim Rng As Range, LstRw As Long
Dim Cell As Range
Dim vNum As Variant, c As Range, y
LstRw = Cells(Rows.Count, "E").End(xlUp).Row
Set Rng = Range("E2:E" & LstRw)
Set cUnique = New Collection
On Error Resume Next
For Each Cell In Rng.Cells
cUnique.Add Cell.Value & Cell.Offset(, 1), CStr(Cell.Value & Cell.Offset(, 1))
Next Cell
On Error GoTo 0
y = 1
For Each vNum In cUnique
For Each c In Rng.Cells
If c & c.Offset(, 1) = vNum Then
c.Offset(, -1) = y
End If
Next c
y = y + 1
Next vNum
End Sub