I have a table with address data. I enter these via a user form. AddressID, LastName, FirstName, ZipCode,City
When I click on the SaveButton, I want to check whether the address entered (without AddressID ) is already in the shAdress table.
For example
AddressID, LastName, FirstName, ZipCode,City
1 May Paul 67105 Berlin
2 May Paul 67106 Berlin that’s ok
3 May Paul 67105 Berlin this is wrong!

Up to now, I have been writing the data to the table and then checking for duplicates. However, it would make more sense to check the data before slicing. Can anyone help me with how to do this?

My function to check after insert in the sheet

Function CheckforDuplicateListObject(wksTab As Worksheet, TableName As String) As Boolean

Dim LastRow As Long, LastRowNew As Long
Dim LastCol As Long
Dim i As Long
Dim vardat() As Variant

'Switch off calculations
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False
Application.EnableEvents = False

With wksTab
    .Activate
    
    'Number of rows and columns to be checked
    LastRow = .Range(TableName).Rows.Count
    LastCol = Range(TableName).Columns.Count
    
    'Form data field without ID column
    'Number of columns varies depending on the table!!!
    ReDim vardat(0 To LastCol - 2) As Variant
    
    For i = 2 To LastCol
        vardat(i - 2) = i
    Next i
    
    'Delete duplicate data records with comparison of the data field
    ActiveSheet.ListObjects(TableName).DataBodyRange.RemoveDuplicates Columns:=(vardat), Header:=xlYes
    
    'Number of remaining lines
    LastRowNew = .Range(TableName).Rows.Count
End With

''Berechnungen wieder einschalten
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
Application.EnableEvents = True

If LastRowNew < LastRow Then
    CheckforDuplicateListObject = True
Else
    CheckforDuplicateListObject = False
End If

End Function

Sub testDuplikateListIbjectRows()

If CheckforDuplicateListObject(shListobj, "tbAdressen") = False Then
    MsgBox "Die Daten wurden in die Tabelle eingetragen"
Else
    MsgBox "Die Daten sind bereits vorhanden"
End If

End Sub