Updating Data Using Cursor in VBA

Option Private Module
Option Explicit
Dim conn As ADODB.Connection, dateval As String, day As String, month As String, Yr As String
Dim empCode As String
Dim rst As ADODB.Recordset, querystring, i As Integer, rowcount As Long

Sub updateempDetailsForOracle()
Set conn = New ADODB.Connection
Set rst = New ADODB.Recordset
dateval = ThisWorkbook.Sheets(1).Range("A1")
empCode = ThisWorkbook.Sheets(1).Range("A2")
If InStr(Mid(dateval, 1, 2), "/") > 0 Then
        day = Mid(dateval, 1, 1)
        month = Mid(dateval, 3, 1)
        Yr = Mid(dateval, 5, 4)
Else
        day = Mid(dateval, 1, 2)
        month = Mid(dateval, 4, 2)
        Yr = Mid(dateval, 7, 4)

End If

querystring = "update empDetails set empDOJ=" & Chr(39) & Yr & "-" & month & "-" & day & Chr(39) & " where empCode=" & empCode
i = 1
rowcount = ThisWorkbook.Sheets(1).Range("B" & Rows.Count).End(xlUp).Row
If (rowcount > 1) Then
        ThisWorkbook.Sheets(1).Range("A2:B" & rowcount).ClearContents
End If
    conn.ConnectionString = "Data Source=empDetails;Initial Catalog=dbMentorMenteedetails;uid="*";pwd="*"
    conn.CursorLocation = adUseServer
    conn.Open
    rst.Open querystring, conn, adOpenDynamic
       
        conn.Close
        Set rst = Nothing
        Set conn = Nothing
End Sub